Add labeler

Author: sue445

.github/labeler.yml

@@ -0,0 +1,7 @@
+go-module:
+  - changed-files:
+      - any-glob-to-any-file: "ruby/**/*"
+
+ruby-gem:
+  - changed-files:
+      - any-glob-to-any-file: "gem/**/*"

.github/workflows/build.yml

@@ -10,6 +10,7 @@ on:
       - synchronize
       - reopened
     paths-ignore:
+      - ".github/labeler.yml"
       - ".github/release.yml"
       - ".github/workflows/patch_for_go_gem.yml"
       - "_benchmark/**"

.github/workflows/labeler.yml

@@ -0,0 +1,13 @@
+name: "Pull Request Labeler"
+
+on:
+  - pull_request_target
+
+jobs:
+  labeler:
+    permissions:
+      contents: read
+      pull-requests: write
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/labeler@v5