Add labeler for PRs.

Author: TBoshoven

.github/labeler.yaml

@@ -0,0 +1,15 @@
+ci:
+- '.circleci/**/*'
+- '.github/**/*'
+minecraft 1.12.2:
+# Looks like Labeler doesn't match directories starting on '.' by default.
+# Include at least the root-level ones.
+- '.*'
+- '.*/**/*'
+- '**/*'
+mod magic doorknob:
+- 'MagicDoorknob/**/*'
+- 'build.gradle'
+mod magic mirror:
+- 'MagicMirror/**/*'
+- 'build.gradle'

.github/workflows/labeler.yaml

@@ -0,0 +1,14 @@
+name: Pull Request Labeler
+on:
+  pull_request:
+    branches:
+    - 1.12.2
+
+jobs:
+  triage:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/labeler@v3-preview
+        with:
+          configuration-path: .github/labeler.yaml
+          repo-token: "${{ secrets.GITHUB_TOKEN }}"