fix: Use pipenv when building docs

Author: haroldadmin

.github/workflows/docs.yml

@@ -36,7 +36,7 @@ jobs:
 
       - name: Build mkdocs website
         working-directory: ./docs
-        run: mkdocs build --clean --verbose
+        run: pipenv mkdocs build --clean --verbose
 
       - name: Deploy mkdocs website
         uses: peaceiris/actions-gh-pages@v3