Try this

Author: jrfnl

.github/workflows/ci.yml

@@ -150,7 +150,7 @@ jobs:
 
       # Check that the rulesets don't throw unnecessary errors for the compat libraries themselves.
       # Note: the polyfills for PHP 5.4 - 7.1 have been decoupled from the monorepo at version 1.19.
-      # The polyfills for PHP 7.2 has been decoupled from the monorepo at version 1.30.
+      # The polyfills for PHP 7.2 have been decoupled from the monorepo at version 1.30.
       # These are no longer updated.
       - name: Test running against the polyfills - polyfills 5.4-7.1
         run: |

composer.json

@@ -33,6 +33,7 @@
     "symfony/polyfill-php54": "1.19",
     "symfony/polyfill-php55": "1.19",
     "symfony/polyfill-php56": "1.19",
+    "symfony/polyfill-util": "1.19",
     "symfony/polyfill-php70": "1.19",
     "symfony/polyfill-php71": "1.19",
     "symfony/polyfill-php72": "1.30",