Add tox -e lint to GHA

.github/workflows/lint-code.yml

@@ -0,0 +1,26 @@
+name: Run and Apply Linter
+on:
+  workflow_dispatch:
+  pull_request:
+    branches: [ master ]
+jobs:
+  run-and-apply:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout main branch
+        uses: actions/checkout@v2
+        with:
+          ref: ${{ github.event.pull_request.head.ref }}
+      - name: Install dependencies
+        run: |
+          pip install --upgrade pip setuptools wheel
+          pip install "tox<4.0.0"
+      - name: Permission workaround
+        run: git config --global --add safe.directory "$GITHUB_WORKSPACE"
+      - name: Run linter
+        run: tox -e lint
+      - name: Commit changes
+        uses: EndBug/add-and-commit@v9
+        with:
+          message: 'Commit automated linter changes'
+          add: '.'