Merge branch '5.1'

* 5.1:
  [PhpUnitBridge] fix leftover
  [PhpUnitBridge] fix installing under PHP >= 8
  Use ">=" for the "php" requirement
  bump icu 67.1
  [DI] Remove preload primitive types
  [Validator] Add missing translations of nn locale
  [HttpKernel] Fix that the `Store` would not save responses with the X-Content-Digest header present
  [Intl] bump icu 67.1
  [Validator] allow passing a validator to Validation::createCallable()

composer.json

@@ -20,7 +20,7 @@
         }
     ],
     "require": {
-        "php": "^7.2.5",
+        "php": ">=7.2.5",
         "symfony/polyfill-php80": "^1.15"
     },
     "require-dev": {