Fix test

Author: ondrejmirtes

.github/workflows/e2e-tests.yml

@@ -179,7 +179,7 @@ jobs:
               ../../bin/phpstan
               echo -en '\n' >> build/CustomRule.php
               OUTPUT=$(../../bin/phpstan 2>&1)
-              grep 'Warning: Result cache might not behave correctly' <<< "$OUTPUT"
+              grep 'Result cache might not behave correctly' <<< "$OUTPUT"
               grep 'ResultCache8E2E\\CustomRule' <<< "$OUTPUT"
 
     steps: