Update branch in docs workflow.

Author: fkdosilovic

.github/workflows/docs.yml

@@ -24,7 +24,7 @@ jobs:
         path: docs/build/html/
     - name: Deploy
       uses: peaceiris/actions-gh-pages@v3
-      if: github.ref == 'refs/heads/main'
+      if: github.ref == 'refs/heads/master'
       with:
         github_token: ${{ secrets.GITHUB_TOKEN }}
         publish_dir: docs/build/html