Update .github/workflows/wycheproof.yml

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: MarkAtwood

.github/workflows/wycheproof.yml

@@ -47,6 +47,7 @@ jobs:
         uses: actions/checkout@v4
         with:
           repository: wolfSSL/wychcheck
+          ref: ${{ vars.WYCHCHECK_REF }}
           path: wychcheck
 
       - name: Init wycheproof vectors submodule