Update actions/upload-pages-artifact

Old one uses deprecated version of actions/upload-artifact

Author: Apanatshka

.github/workflows/docs.yml

@@ -46,7 +46,7 @@ jobs:
       - name: Build documentation
         run: mkdocs build
       - name: Upload artifact
-        uses: actions/upload-pages-artifact@v2
+        uses: actions/upload-pages-artifact@v3
         with:
           path: site/
 
@@ -60,4 +60,4 @@ jobs:
     steps:
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v2
+        uses: actions/deploy-pages@v2