docs(readme): add badge for monthly cask

Run once a day only, and pass in cache flag to keep download totals
accurate over time.

.github/workflows/update-metadata.yml

@@ -3,7 +3,7 @@ name: Update Metadata
 concurrency: jimeh/emacs-builds/update-metadata
 on:
   schedule:
-    - cron: "0 0,12 * * *"
+    - cron: "0 0 * * *"
   workflow_dispatch:
 
 jobs:
@@ -19,7 +19,9 @@ jobs:
           go-version: "1.21"
       - name: update total downloads shield JSON
         run: >-
-          go run . badges downloads -o total-downloads/shield.json
+          go run . badges downloads
+          --output total-downloads/shield.json
+          --cache total-downloads/.cache.json
         env:
           GITHUB_TOKEN: ${{ github.token }}
       - name: commit and push changes to meta branch

README.md

@@ -10,7 +10,7 @@
   <a href="https://github.com/jimeh/emacs-builds/releases/latest"><img alt="GitHub release (stable)" src="https://img.shields.io/endpoint?url=https%3A%2F%2Fraw.githubusercontent.com%2Fjimeh%2Fhomebrew-emacs-builds%2Fmeta%2FCasks%2Femacs-app%2Fshield.json"></a>
   <a href="https://github.com/jimeh/emacs-builds/releases?q=pretest&expanded=true"><img alt="GitHub release (pretest)" src="https://img.shields.io/endpoint?url=https%3A%2F%2Fraw.githubusercontent.com%2Fjimeh%2Fhomebrew-emacs-builds%2Fmeta%2FCasks%2Femacs-app-pretest%2Fshield.json"></a>
   <a href="https://github.com/jimeh/emacs-builds/releases?q=master&expanded=true"><img alt="GitHub release (nightly)" src="https://img.shields.io/endpoint?url=https%3A%2F%2Fraw.githubusercontent.com%2Fjimeh%2Fhomebrew-emacs-builds%2Fmeta%2FCasks%2Femacs-app-nightly%2Fshield.json"></a>
-  <a href="https://github.com/jimeh/emacs-builds/releases?q=emacs-29&expanded=true"><img alt="GitHub release (nightly@emacs-29)" src="https://img.shields.io/endpoint?url=https%3A%2F%2Fraw.githubusercontent.com%2Fjimeh%2Fhomebrew-emacs-builds%2Fmeta%2FCasks%2Femacs-app-nightly-29%2Fshield.json"></a>
+  <a href="https://github.com/jimeh/emacs-builds/releases?q=master&expanded=true"><img alt="GitHub release (monthly)" src="https://img.shields.io/endpoint?url=https%3A%2F%2Fraw.githubusercontent.com%2Fjimeh%2Fhomebrew-emacs-builds%2Fmeta%2FCasks%2Femacs-app-monthly%2Fshield.json"></a>
   <a href="https://github.com/jimeh/emacs-builds/issues/7"><img alt="GitHub release (known good nightly)" src="https://img.shields.io/endpoint?url=https%3A%2F%2Fraw.githubusercontent.com%2Fjimeh%2Fhomebrew-emacs-builds%2Fmeta%2FCasks%2Femacs-app-good%2Fshield.json"></a>
   <a href="https://github.com/jimeh/emacs-builds/issues"><img alt="GitHub issues" src="https://img.shields.io/github/issues-raw/jimeh/emacs-builds?style=flat&logo=github&logoColor=white"></a>
   <a href="https://github.com/jimeh/emacs-builds/pulls"><img alt="GitHub pull requests" src="https://img.shields.io/github/issues-pr-raw/jimeh/emacs-builds?style=flat&logo=github&logoColor=white"></a>
@@ -56,8 +56,11 @@
 
 ## System Requirements
 
-- macOS 11.x (Big Sur) or later (uses Rosetta2 on Apple Silicon machines).
-- Xcode Command Line Tools for native compilation (Emacs 28.x and later).
+- macOS 13 Ventura or later for Apple Silicon builds.
+- macOS 12 Monterey or later for Intel builds, which can run on Apple Silicon
+  via Rosetta2.
+- Xcode Command Line Tools to use native compilation in Emacs, available since
+  28.x.
 
 ## Installation
 
@@ -84,32 +87,53 @@ for at least a day or two without any obvious issues.
    brew tap jimeh/emacs-builds
    ```
 2. Install one of the available casks:
-   - `emacs-app` for the latest stable release of Emacs (includes native-comp
-     since v28.1):
+   - `emacs-app` — Latest stable release of Emacs.
      ```
      brew install --cask emacs-app
      ```
-   - `emacs-app-pretest` for the latest pretest build from Emacs:
+   - `emacs-app-pretest` — Latest pretest build of Emacs.
      ```
      brew install --cask emacs-app-pretest
      ```
-   - `emacs-app-nightly` for the latest nightly build from Emacs' `master`
-     branch:
+   - `emacs-app-nightly` — Build of Emacs from the `master` branch, updated
+     every night.
      ```
      brew install --cask emacs-app-nightly
      ```
+   - `emacs-app-monthly` — Build of Emacs from the `master` branch, updated on
+     the 1st of each month. These includes native Apple Silicon support.
+     ```
+     brew install --cask emacs-app-monthly
+     ```
    - `emacs-app-good` for the latest known good nightly build listed on [#7][7]:
      ```
      brew install --cask emacs-app-good
      ```
-   - `emacs-app-nightly-29` for the latest Emacs 29.x nightly build from the
-     `emacs-29` branch:
-     ```
-     brew install --cask emacs-app-nightly-29
-     ```
 
 [7]: https://github.com/jimeh/emacs-builds/issues/7
 
+## Apple Silicon
+
+Native builds for Apple Silicon is supported, but currently GitHub's M1-based
+Actions Runners are prohibitively expensive for nightly builds. Intel builds
+though do work on Apple Silicon machines via Rosetta2, with a minor performance
+impact.
+
+Due to the costs, Apple Silicon builds are for now only scheduled for the 1st of
+each month. The `emacs-app-monthly` Homebrew Cask will always be pointing at a
+release that includes Intel and Apple Silicon builds.
+
+Builds for stable releases of Emacs will also include both Intel and Apple
+Silicon builds.
+
+### Costs
+
+At time of writing (2023-11-21), an average Apple Silicon build uses around 17
+minutes of billable time, at a cost of $0.16 USD per minute, that comes out to
+around $2.72 per build. I am considering enabling sponsorship on this repository
+in an effort to cover the costs for more frequent Apple Silicon builds, and will
+update here if/when I have any news.
+
 ## Use Emacs.app as `emacs` CLI Tool
 
 ### Installed via Homebrew Cask
@@ -192,3 +216,21 @@ GitHub Actions workflow run which produced the build.
 Please see [Issues][] for details of things to come, or to report issues.
 
 [issues]: https://github.com/jimeh/emacs-builds/issues
+
+## News / Recent Changes
+
+### 2023-11-22 — Apple Silicon builds, drop macOS 11 support
+
+Apple Silicon builds are now available, but limited to stable releases, and
+nightly builds on the 1st of each month due to the cost of using M1-based
+runners on GitHub Actions. Apple Silicon builds also require macOS 13 Ventura,
+as that is the oldest macOS version available on M1-based runners.
+
+Additionally, Intel builds minimum required macOS version has been increased
+from macOS 11 Big Sur, to macOS 12 Monterey. This was needed as Homebrew no
+longer supports Big Sur, leading to very lengthy and error prone builds as all
+Homebrew dependencies had to be installed from source.
+
+If dropping support for macOS 11 turns out to be a big issue, it may be possible
+to offer macOS 11 compatible builds on a less frequent schedule similar to what
+we're doing with Apple Silicon.