add mkdocs build workflow (polkadot-developers#224)

Co-authored-by: Ilaria Enache <[email protected]>

Author: ilariae

.github/workflows/check-mkdocs-build.yml

@@ -0,0 +1,46 @@
+name: CheckMkDocsBuild
+on:
+  # Trigger the workflow on a new pull request on master
+  pull_request_target:
+    branches:
+      - master
+
+jobs:
+  build-docs-site:
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.10.12'
+
+      - name: Allow to move dotfiles
+        run: |
+          # move also dotfile with *
+          shopt -s dotglob
+
+      - name: Clone Moonbeam MKDocs
+        run: |
+          # clone mkdocs repo locally
+          git clone https://${{ secrets.REPO_SCOPED_TOKEN }}@github.com/papermoonio/polkadot-mkdocs
+
+      - name: Move polkadot-docs contents to mkdocs repository
+        run: |
+          mkdir polkadot-mkdocs/polkadot-docs
+          find . -mindepth 1 -maxdepth 1 ! -name 'polkadot-mkdocs' -exec mv {} polkadot-mkdocs/polkadot-docs/ \;
+
+      - name: Install pip requirements
+        run: |
+          cd polkadot-mkdocs
+          # upgrade pip
+          pip3 install --upgrade pip setuptools==65.7.0
+          # install dependencies quietly
+          pip3 install -r requirements.txt &> /dev/null && echo "Dependencies installed" || echo "Error while installing dependencies"
+
+      - name: Build mkdocs
+        run: |
+          cd polkadot-mkdocs
+          # change destination build folder in mkdocs YAML to local site/
+          sed -i 's/site_dir.*/site_dir: site/' mkdocs.yml
+          # build project
+          python3 -m mkdocs build