Add a github action to validate syntax post-commit

While we don't use the github workflow for our development, it doesn't
hurt to get a post-commit notification when somebody forgot to validate
things pre-commit (using the hook we have). This hook also runs with
exactly the version of python/pycodestyle that we are using in
production, which might help someone.

diff --git a/.github/workflows/validate-syntax.yaml b/.github/workflows/validate-syntax.yaml
new file mode 100644 (file)
index 0000000..e3d8238
--- /dev/null
+++ b/.github/workflows/validate-syntax.yaml
@@ -0,0 +1,25 @@
+name: Validate python syntax
+
+on: [push, pull_request]
+
+jobs:
+  validate:
+
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: [3.7]
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v2
+      with:
+        python-version: ${{ matrix.python-version }}
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install pycodestyle==2.4.0
+    - name: Validate with pycodestyle
+      run: |
+        pycodestyle