[5.4] Add setKeyType() method to Eloquent abstract Model (#18354)

* Add missing setKeyType method to Eloquent abstract Model.  (#18353)

* Update Model.php

src/Illuminate/Database/Eloquent/Model.php

@@ -1105,7 +1105,7 @@ public function getQualifiedKeyName()
     }
 
     /**
-     * Get the auto incrementing key type.
+     * Get the auto-incrementing key type.
      *
      * @return string
      */
@@ -1114,6 +1114,19 @@ public function getKeyType()
         return $this->keyType;
     }
 
+    /**
+     * Set the data type for the primary key.
+     *
+     * @param  string  $type
+     * @return $this
+     */
+    public function setKeyType($type)
+    {
+        $this->keyType = $type;
+
+        return $this;
+    }
+
     /**
      * Get the value indicating whether the IDs are incrementing.
      *