Internal: Set strict requirement for PHP version 7.4

Author: ywarnier

main/inc/lib/api.lib.php

@@ -20,7 +20,7 @@
  */
 
 // PHP version requirement.
-define('REQUIRED_PHP_VERSION', '7.1');
+define('REQUIRED_PHP_VERSION', '7.4');
 define('REQUIRED_MIN_MEMORY_LIMIT', '128');
 define('REQUIRED_MIN_UPLOAD_MAX_FILESIZE', '10');
 define('REQUIRED_MIN_POST_MAX_SIZE', '10');