ci: Install actions-label-commenter"

https://github.com/peaceiris/actions-label-commenter

.github/workflows/label-commenter.yml

@@ -0,0 +1,27 @@
+name: Label Commenter
+
+on:
+  issues:
+    types:
+      - labeled
+      - unlabeled
+  pull_request_target:
+    types:
+      - labeled
+      - unlabeled
+
+permissions:
+  contents: read
+  issues: write
+  pull-requests: write
+
+jobs:
+  comment:
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Label Commenter
+        uses: peaceiris/actions-label-commenter@v1
+        env:
+          RUNNER_DEBUG: 1