Add missing commit steps

.github/workflows/snapshot.yml

@@ -1,6 +1,14 @@
 name: 📸
 
 on:
+  push:
+    branches:
+      - main
+    paths-ignore:
+      - '**.md'
+  pull_request:
+    paths-ignore:
+      - '**.md'
   schedule:
     # Every 10:42 JST
     # https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#schedule
@@ -12,6 +20,16 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@v4
+      - name: Prepare Git user
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+      - name: Prepare Git branch
+        id: prepare-branch
+        run: |
+          started_at="$(date +%Y%m%d-%H%M%S)"
+          git switch -c "${{ github.sha }}-${started_at}"
+          echo started_at="$started_at" | tee -a "$GITHUB_OUTPUT"
       - name: Set up Go
         uses: actions/setup-go@v5
         with:
@@ -23,3 +41,19 @@ jobs:
           version: '3.36.0' # selfup {"extract":"\\d\\.\\d+\\.\\d+","replacer":["task", "--version"], "nth": 3}
       - run: |
           task snapshot | tee -a snapshot.txt
+      - name: Update related CI dependencies
+        run: |
+          git diff-index --quiet HEAD || git commit -m 'Update snapshots' snapshot.txt
+      - name: Count added commits
+        id: count-commits
+        run: |
+          count="$(git rev-list --count origin/${{ github.event.repository.default_branch }}..)"
+          echo "count=${count}" | tee -a "$GITHUB_OUTPUT"
+      - run: git push origin '${{ steps.prepare-branch.outputs.started_at }}'
+        if: ${{ github.event_name != 'pull_request' }} && (steps.count-commits.outputs.count > 0)
+      - name: Create PR
+        if: ${{ github.event_name != 'pull_request' }} && (steps.count-commits.outputs.count > 0)
+        env:
+          GITHUB_TOKEN: ${{ github.token }}
+        run: |
+          gh pr create --base '${{ github.event.repository.default_branch }}' --title 'Update snapshots'