ci(release): simplify release-please setup (#4)

.github/workflows/release-please.yml

@@ -1,16 +1,11 @@
 ---
-on: push
+on:
+  push:
+    branches:
+      - main
 
 jobs:
   release-please:
     runs-on: ubuntu-latest
-    if: github.ref == 'refs/heads/main'
-    outputs:
-      release_created: ${{ steps.release-please.outputs.release_created }}
-      tag_name: ${{ steps.release-please.outputs.tag_name }} # e.g. v1.0.0
-      version: ${{ steps.release-please.outputs.version }} # e.g. 1.0.0
     steps:
-      - uses: google-github-actions/release-please-action@v3
-        id: release-please
-        with:
-          command: manifest
+      - uses: jimeh/release-please-manifest-action@v1