Run downgrade CI on pushes to main (#494)

Co-authored-by: ChrisRackauckas-Claude <accounts@chrisrackauckas.com>

Author: ChrisRackauckas-Claude

.github/workflows/Downgrade.yml

@@ -7,7 +7,7 @@ on:
       - 'docs/**'
   push:
     branches:
-      - master
+      - main
     paths-ignore:
       - 'docs/**'
 jobs: