Add docs build validation stage to CI (#4116)

Nice. Thank you

.github/workflows/ci.yaml

@@ -230,3 +230,21 @@ jobs:
           exit_code=${PIPESTATUS[0]}
           echo '```' >> $GITHUB_STEP_SUMMARY
           exit $exit_code
+
+  docs:
+    name: "mkdocs"
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+      - name: "Install Rust toolchain"
+        run: rustup show
+      - uses: Swatinem/rust-cache@v2
+      - name: "Install dependencies"
+        run: pip install -r docs/requirements.txt
+      - name: "Update README File"
+        run: python scripts/transform_readme.py --target mkdocs
+      - name: "Generate docs"
+        run: python scripts/generate_mkdocs.py
+      - name: "Build docs"
+        run: mkdocs build --strict