ci: Add an automatic labeler action

To automate a bit.

.github/labeler.yml

@@ -0,0 +1,6 @@
+area/prepare-root:
+- src/switchroot/**
+- src/boot
+
+area/rust-bindings:
+- rust-bindings/**

.github/workflows/labeler.yml

@@ -0,0 +1,12 @@
+name: "Pull Request Labeler"
+on:
+- pull_request_target
+
+jobs:
+  triage:
+    permissions:
+      contents: read
+      pull-requests: write
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/labeler@v4