Add GitHub action for auto-labeling PRs (#1438)

At deployment time, we don't have a way within Teletraan to differentiate which commits are relevant to that service. With this GHA, we will be able to look at the diff in GitHub and filter by labels depending on which service we are deploying.

https://github.com/actions/labeler

.github/labeler.yml

@@ -0,0 +1,12 @@
+deploy-agent:
+  - changed-files:
+    - any-glob-to-any-file: deploy-agent/**
+deploy-board:
+  - changed-files:
+    - any-glob-to-any-file: deploy-board/**
+deploy-sentinel:
+  - changed-files:
+    - any-glob-to-any-file: deploy-sentinel/**
+deploy-service:
+  - changed-files:
+    - any-glob-to-any-file: deploy-service/**

.github/workflows/labeler.yml

@@ -0,0 +1,16 @@
+name: "Pull Request Labeler"
+
+on:
+  - pull_request_target
+
+jobs:
+  labeler:
+    permissions:
+      contents: read
+      pull-requests: write
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/labeler@v5
+      with:
+        repo-token: "${{ secrets.GITHUB_TOKEN }}"
+        sync-labels: true