feat(dev): introduce Pull Request Labeler

.github/labeler.yml

+'⚙️Server':
+- packages/backend/**/*
+
+'🖥️Client':
+- packages/client/**/*

.github/workflows/labeler.yml

+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
+      with:
+        repo-token: "${{ secrets.GITHUB_TOKEN }}"