chore: new lint job

Author: jackwotherspoon

.github/workflows/formatter.yml

@@ -0,0 +1,35 @@
+# Copyright 2022 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+name: Lint
+on: [pull_request]
+
+jobs:
+  build:
+    name: Run lint
+    runs-on: ubuntu-latest
+    steps:
+      - name: Setup Python
+        uses: actions/setup-python@v3
+        with:
+          python-version: "3.9"
+      
+      - name: Install nox
+        run: pip install nox
+
+      - name: Checkout code
+        uses: actions/checkout@v3
+
+      - name: Run nox lint session
+        run: nox --sessions lint

.github/workflows/lint.yml

@@ -0,0 +1,19 @@
+from __future__ import absolute_import
+import os
+import nox
+
+BLACK_PATHS = ["iam_groups_authn"]
+
+if os.path.exists("samples"):
+    BLACK_PATHS.append("samples")
+
+
+@nox.session
+def lint(session):
+    """Run linters.
+    Returns a failure if the linters find linting errors or sufficiently
+    serious code quality issues.
+    """
+    session.install("-r", "requirements-test.txt")
+    session.install("-r", "requirements.txt")
+    session.run("black", "--check", *BLACK_PATHS)