make sure we're in the right directory

.github/workflows/sage-test.yml

@@ -108,6 +108,7 @@ jobs:
         run: |
           SAGENAME=sage-test
           SITENAME=wpcm-sage-install-tests
+          cd ~/pantheon-local-copies/$SITENAME
           composer install-sage || exit_code=$?
           if [[ -n "${exit_code}" ]]; then
             echo "❌ Sage Install Script Failed with exit code ${exit_code}"