Add labler github action for auto labeling of PRs

Signed-off-by: Hung-Han (Henry) Chen <1474479+chenhunghan@users.noreply.github.com>

.github/labeler-config.yml

@@ -0,0 +1,13 @@
+---
+area/ui:
+  - src/renderer/**/*
+area/test:
+  - integration/**/*
+  - __mocks__/**/*
+area/extension:
+  - extensions/**/*
+  - src/extensions/**/*
+area/documentation:
+  - READEME.md
+dependencies:
+  - yarn.lock

.github/workflows/labeler.yml

@@ -0,0 +1,14 @@
+---
+name: "Pull Request Labeler"
+
+'on':
+  - pull_request
+
+jobs:
+  triage:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/labeler@v2
+        with:
+          repo-token: "${{ secrets.GITHUB_TOKEN }}"
+          configuration-path: .github/labeler-config.yml