Fix docs deployment (file permissions)

See: actions/deploy-pages#188

.github/workflows/docs.yml

@@ -34,10 +34,16 @@ jobs:
         run: RUSTDOCFLAGS="-D warnings --cfg docsrs" cargo doc --workspace --no-deps --all-features
       - name: glue in an index
         run: echo "<meta http-equiv=\"refresh\" content=\"0; url=rsdd\">" > target/doc/index.html
+      - name: Force correct file permissions
+        run: |
+          chmod -c -R +rX "target/doc" |
+          while read line; do
+            echo "::warning title=Invalid file permissions automatically fixed::$line"
+          done
       - name: Upload artifact
         uses: actions/upload-pages-artifact@v1
         with:
           path: 'target/doc'
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v1
+        uses: actions/deploy-pages@v2