ci: add release automation (#78)

* ci: add release automation

* fixup! ci: add release automation

* ci: delete job permission

Because we use app token that has the permissions.

Do we need to pass permission to GITHUB_TOKEN?

Author: Omochice

.github/release-please-config.json

@@ -0,0 +1,14 @@
+{
+  "packages": {
+    ".": {
+      "changelog-path": "CHANGELOG.md",
+      "release-type": "simple",
+      "bump-minor-pre-major": false,
+      "bump-patch-for-minor-pre-major": false,
+      "draft": false,
+      "prerelease": false,
+      "always-update": true
+    }
+  },
+  "$schema": "https://raw.githubusercontent.com/googleapis/release-please/main/schemas/config.json"
+}

.github/workflows/release.yaml

@@ -0,0 +1,25 @@
+name: Release workflow
+
+on:
+  push:
+    branches:
+      - main
+
+permissions: {}
+
+jobs:
+  release-please:
+    timeout-minutes: 5
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/create-github-app-token@29824e69f54612133e76f7eaac726eef6c875baf # v2.2.1
+        id: app-token
+        with:
+          app-id: ${{ secrets.RELEASE_APP_ID }}
+          private-key: ${{ secrets.RELEASE_PRIVATE_KEY }}
+          permission-contents: write
+          permission-pull-requests: write
+      - uses: googleapis/release-please-action@16a9c90856f42705d54a6fda1823352bdc62cf38 # v4.4.0
+        with:
+          token: ${{ steps.app-token.outputs.token }}
+          release-type: simple