Added format check gh action workflow

.github/workflows/format-check.yml

@@ -0,0 +1,27 @@
+name: Format Check
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      max-parallel: 4
+      matrix:
+        python-version: [3.7]
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v1
+      with:
+        python-version: ${{ matrix.python-version }}
+    - name: Install dependencies
+      run: |
+        pip install tox
+    - name: Execute Format Check
+      run: |
+        tox -e format-check

gilt/shell.py

@@ -43,7 +43,7 @@ class NotFoundError(Exception):
     "--config",
     default="gilt.yml",
     help="Path to config file.  Default gilt.yml",
-    type=click.File('r'),
+    type=click.File("r"),
 )
 @click.option(
     "--debug/--no-debug",