Fix internal deprecations in ColumnTypeGuesser.php (#889)

Author: gnutix

src/Faker/ORM/Doctrine/ColumnTypeGuesser.php

@@ -27,7 +27,7 @@ public function guessFormat($fieldName, ClassMetadata $class)
         switch ($type) {
             case 'boolean':
                 return static function () use ($generator) {
-                    return $generator->boolean;
+                    return $generator->boolean();
                 };
 
             case 'decimal':
@@ -66,14 +66,14 @@ public function guessFormat($fieldName, ClassMetadata $class)
 
             case 'text':
                 return static function () use ($generator) {
-                    return $generator->text;
+                    return $generator->text();
                 };
 
             case 'datetime':
             case 'date':
             case 'time':
                 return static function () use ($generator) {
-                    return $generator->datetime;
+                    return $generator->datetime();
                 };
 
             case 'datetime_immutable':