feat(ci): add release-please and improve renovate auto-merge

.github/workflows/release-please.yml

@@ -0,0 +1,19 @@
+name: Release Please
+
+on:
+  push:
+    branches: [main]
+
+permissions: {}
+
+jobs:
+  release-please:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      pull-requests: write
+    steps:
+      - uses: googleapis/release-please-action@v4
+        with:
+          config-file: release-please-config.json
+          manifest-file: .release-please-manifest.json

.release-please-manifest.json

@@ -0,0 +1,3 @@
+{
+  ".": "1.0.0"
+}

VERSION

@@ -0,0 +1 @@
+1.0.0

release-please-config.json

@@ -0,0 +1,21 @@
+{
+  "$schema": "https://raw.githubusercontent.com/googleapis/release-please/main/schemas/config.json",
+  "packages": {
+    ".": {
+      "release-type": "simple",
+      "version-file": "VERSION"
+    }
+  },
+  "bump-minor-pre-major": true,
+  "include-v-in-tag": true,
+  "changelog-sections": [
+    {"type": "feat", "section": "Features"},
+    {"type": "fix", "section": "Bug Fixes"},
+    {"type": "perf", "section": "Performance"},
+    {"type": "docs", "section": "Documentation", "hidden": true},
+    {"type": "chore", "section": "Miscellaneous", "hidden": true},
+    {"type": "refactor", "section": "Refactoring", "hidden": true},
+    {"type": "test", "section": "Tests", "hidden": true},
+    {"type": "ci", "section": "CI", "hidden": true}
+  ]
+}

renovate.json

@@ -2,5 +2,15 @@
   "$schema": "https://docs.renovatebot.com/renovate-schema.json",
   "extends": [
     "config:recommended"
+  ],
+  "packageRules": [
+    {
+      "description": "Auto-merge official GitHub Actions (including major versions)",
+      "matchDatasources": ["github-actions"],
+      "matchPackagePrefixes": ["actions/"],
+      "automerge": true,
+      "automergeType": "squash",
+      "minimumReleaseAge": "1 day"
+    }
   ]
 }