updates min php version to 7.4 to match the oldest version platform.sh supports

Author: gilzow

composer.json

@@ -9,7 +9,7 @@
         }
     ],
     "require": {
-        "php": ">=7.2"
+        "php": ">=7.4"
     },
     "require-dev": {
         "phpunit/phpunit": "^8.5"
@@ -26,7 +26,7 @@
     },
     "config": {
         "platform": {
-            "php": "7.2"
+            "php": "7.4"
         }
     }
 }