CI: disable Downgrade workflow until ecosystem stabilizes

Co-Authored-By: Chris Rackauckas <accounts@chrisrackauckas.com>

Author: ChrisRackauckas

.github/workflows/Downgrade.yml

@@ -12,6 +12,7 @@ on:
       - 'docs/**'
 jobs:
   test:
+    if: false
     runs-on: ubuntu-latest
     strategy:
       matrix: