add docs workflow

.github/workflows/docs.yml

@@ -0,0 +1,21 @@
+name: Build Docs
+
+on:
+  push:
+    paths:
+      - "docs/**"
+  workflow_dispatch:
+
+jobs:
+  docs:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/setup-python@v4
+        with:
+          python-version: 3.x
+      - uses: actions/cache@v2
+        with:
+          path: .cache
+          key: ${{ github.ref }}
+      - run: pip install mkdocs-material jupyter nbconvert mkdocs-jupyter
+      - run: mkdocs gh-deploy --force