Merge pull request #18 from dayspring-tech/hotfix/fix_covariant

fix missing return types on Column

Author: jwong-dayspring

Tests/Fixtures/Column.php

@@ -18,7 +18,7 @@ public function __construct(private $name, protected $type)
         $this->phpName = ucfirst($this->name);
     }
 
-    public function isText()
+    public function isText(): bool
     {
         if (!$this->type) {
             return false;
@@ -34,7 +34,7 @@ public function getSize()
         return $this->isText() ? 255 : 0;
     }
 
-    public function isNotNull()
+    public function isNotNull(): bool
     {
         return 'id' === $this->name;
     }