Add PR auto-labeler

Author: fwcd

.github/labeler.yml

@@ -0,0 +1,47 @@
+build:
+  - buildSrc/**
+  - server/build.gradle.kts
+  - shared/build.gradle.kts
+  - build.gradle.kts
+  - gradle
+  - gradle.properties
+  - gradlew
+  - gradlew.bat
+  - settings.gradle.kts
+
+ci-cd:
+  - .github/**
+
+code completion:
+  - server/src/main/kotlin/org/javacs/kt/completion/**
+  - server/src/test/resources/completions/**
+
+code quality:
+  - server/src/test/**
+  - shared/src/test/**
+
+dependency resolution:
+  - shared/src/main/kotlin/org/javacs/kt/classpath/**
+
+diagnostics:
+  - server/src/main/kotlin/org/javacs/kt/diagnostic/**
+
+docker:
+  - Dockerfile
+
+editor support:
+  - EDITORS.md
+
+formatting:
+  - server/src/main/kotlin/org/javacs/kt/formatting/**
+  - server/test/resources/formatting/**
+
+gradle:
+  - shared/src/main/kotlin/org/javacs/kt/classpath/Gradle*
+  - shared/src/main/resources/*.gradle
+
+index:
+  - server/src/main/kotlin/org/javacs/kt/index/**
+
+maven:
+  - shared/src/main/kotlin/org/javacs/kt/classpath/Maven*

.github/workflows/labeler.yml

@@ -0,0 +1,14 @@
+name: Pull Request Labeler
+on:
+  - pull_request_target
+
+jobs:
+  triage:
+    permissions:
+      contents: read
+      pull-requests: write
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/labeler@v4
+        with:
+          dot: true