Fix branch name

Author: multiplemonomials

.github/workflows/build-and-deploy.yml

@@ -21,9 +21,9 @@ jobs:
         source .venv/bin/activate
         mkdocs build
 
-    # Copy the built files to the server (only if this is on master branch)
+    # Copy the built files to the server (only if this is on main branch)
     - name: Deploy Site
-      if: github.ref == 'refs/heads/master'
+      if: github.ref == 'refs/heads/main'
       uses: easingthemes/[email protected]
       with:
         SSH_PRIVATE_KEY: ${{ secrets.SSH_PRIVATE_KEY }}