github: use labeler actions (#148)

Signed-off-by: Koichi Shiraishi <[email protected]>

Author: zchee

.github/labeler.yaml

@@ -0,0 +1,11 @@
+# https://github.com/actions/labeler
+---
+
+area/ci:
+- .github/**
+
+area/msgpack:
+- msgpack/**/*.go
+
+area/nvim:
+- nvim/**/*.go

.github/workflows/labeler.yaml

@@ -0,0 +1,18 @@
+name: Pull Request Labeler
+
+on:
+  - pull_request
+
+jobs:
+  triage:
+    runs-on: ubuntu-22.04
+
+    permissions:
+      contents: read
+      pull-requests: write
+
+    steps:
+      - uses: actions/labeler@v4
+        with:
+          repo-token: "${{ secrets.GITHUB_TOKEN }}"
+          configuration-path: ".github/labeler.yaml"