make sure to lint markdown too

.github/workflows/lint.yml

@@ -0,0 +1,22 @@
+name: lint
+on:
+  # check on PRs, and manual triggers
+  pull_request:
+      paths:
+       - '**.py'
+       - 'requirements.txt'
+       - '.github/workflows/*.yml'
+       - "*.md"
+  workflow_dispatch:
+
+jobs:
+  pre-commit:
+    name: pre-commit
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: "3.9"
+          cache: 'pip' # caching pip dependencies
+      - uses: pre-commit/[email protected]