Explicitly specify benchmarks repo for checkout (#13)

Author: connoraird

.github/workflows/regression-test.yaml

@@ -48,6 +48,7 @@ jobs:
         uses: actions/checkout@v5
         with:
           fetch-depth: 0
+          repository: glass-dev/glass-benchmarks
 
       - name: Set up Python
         uses: actions/setup-python@v6