ci: Automate PR labeling (#17)

.github/labels.yaml

@@ -0,0 +1,21 @@
+"Code: Verilator":
+  - changed-files:
+      - any-glob-to-any-file: "verilator/**"
+
+"Code: Verilog Support":
+  - changed-files:
+      - any-glob-to-any-file: "verilog-support/**"
+
+"Code: Spade Support":
+  - changed-files:
+      - any-glob-to-any-file: "spade-support/**"
+
+"Infra: CI":
+  - changed-files:
+      - any-glob-to-any-file: ".github/workflows/*"
+      - any-glob-to-any-file: ".github/labels.yaml"
+
+"Documentation":
+  - changed-files:
+      - any-glob-to-any-file: "**/*.md"
+      - any-glob-to-any-file: "assets/**"

.github/workflows/labeler.yaml

@@ -0,0 +1,15 @@
+name: "Pull Request Labeler"
+on:
+  - pull_request_target
+
+jobs:
+  labeler:
+    permissions:
+      contents: read
+      pull-requests: write
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/labeler@v5
+        with:
+          configuration-path: ".github/labels.yaml"