cd(contracts): use foundry-zksync main branch

Author: hbriese

.github/workflows/tests.yaml

@@ -63,7 +63,7 @@ jobs:
         uses: actions/checkout@v4
         with:
           repository: matter-labs/foundry-zksync
-          ref: 'dev'
+          ref: 'main'
           path: 'foundry-zksync'
 
       - name: 🚧 Add foundry-zksync to PATH