fix: bump minimum supported PHP version to 7.4

Fixes #30 for the v2 series by bumping to a PHP version that does interface inheritance correctly.

Author: weierophinney

composer.json

@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": ">=7.2.0"
+        "php": ">=7.4.0"
     },
     "autoload": {
         "psr-4": {