infra: Add PR labeler

Add a labeler that automatically creates labels when a pull request is created.
(You can edit the labeler by modifying ./.github/labeler.yml.)

https://github.com/thorvg/thorvg/issues/labels

.github/labeler.yml

@@ -0,0 +1,55 @@
+"APIs":
+  - inc/**/*
+
+"binding":
+  - src/bindings/**/*
+
+"documentation":
+  - docs/**/*
+  - README.md
+
+"example":
+  - examples/**/*
+
+"font":
+  - src/loaders/ttf/**/*
+
+"image":
+  - src/loaders/jpg/**/*
+  - src/loaders/external_jpg/**/*
+  - src/loaders/png/**/*
+  - src/loaders/external_png/**/*
+  - src/loaders/webp/**/*
+  - src/loaders/external_webp/**/*
+  - src/loaders/raw/**/*
+  - src/savers/gif/**/*
+
+"svg":
+  - src/loaders/svg/**/*
+
+"tvg":
+  - src/loaders/tvg/**/*
+
+"test":
+  - test/**/*
+
+"tools":
+  - tools/**/*
+
+"infrastructure":
+  - .github/**/*
+  - meson.build
+  - meson_option.txt
+
+"lottie":
+  - src/loaders/lottie/**/*
+
+"raster":
+  - src/renderer/sw_engine/**/*
+  - src/renderer/wg_engine/**/*
+  - src/renderer/gl_engine/**/*
+
+"renderer":
+  - src/renderer/**/*
+  - src/common/**/*
+

.github/workflows/pull_request_label.yml

@@ -0,0 +1,13 @@
+name: Pull Request Labeler
+
+on: [pull_request_target]
+
+jobs:
+  triage:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/labeler@v4
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          sync-labels: true
+