Add github action for python lint

.github/workflows/python-ling.yaml

+name: Python linting
+
+on: [push, pull_request]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Python 3.6
+        uses: actions/setup-python@v2
+        with:
+          # Semantic version range syntax or exact version of a Python version
+          python-version: '3.6'
+          # Optional - x64 or x86 architecture, defaults to x64
+          architecture: 'x64'
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install flake8
+          #if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
+      - name: Lint with flake8
+        run: |
+          # stop the build if there are Python syntax errors or undefined names
+          flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
+          # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
+          flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics