ci: auto-label PRs by changed files

.github/labeler.yml

@@ -0,0 +1,38 @@
+# Path-based labels applied to PRs by .github/workflows/labeler.yml.
+# Uses actions/labeler@v5 match rules.
+
+docs:
+  - changed-files:
+      - any-glob-to-any-file:
+          - "docs/**"
+
+app:
+  - changed-files:
+      - any-glob-to-any-file:
+          - "PyMemoryEditor/app/**"
+
+linux:
+  - changed-files:
+      - any-glob-to-any-file:
+          - "PyMemoryEditor/linux/**"
+
+win32:
+  - changed-files:
+      - any-glob-to-any-file:
+          - "PyMemoryEditor/win32/**"
+
+macOS:
+  - changed-files:
+      - any-glob-to-any-file:
+          - "PyMemoryEditor/macos/**"
+
+# Any change inside the PyMemoryEditor package.
+lib:
+  - changed-files:
+      - any-glob-to-any-file:
+          - "PyMemoryEditor/**"
+
+tests:
+  - changed-files:
+      - any-glob-to-any-file:
+          - "tests/**"

.github/workflows/labeler.yml

@@ -0,0 +1,27 @@
+name: Labeler
+
+on:
+  pull_request_target:
+    types:
+      - opened
+      - synchronize
+      - reopened
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.number || github.ref }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+  pull-requests: write
+
+jobs:
+  label:
+    name: Label PR by changed files
+    runs-on: ubuntu-latest
+    steps:
+      - name: Apply labels
+        uses: actions/labeler@v5
+        with:
+          configuration-path: .github/labeler.yml
+          sync-labels: true