Add Signature::create() method.

Signed-off-by: Mior Muhammad Zaki <crynobone@gmail.com>

src/Signature.php

@@ -28,18 +28,24 @@ public function __construct(string $key, array $attributes)
     }
 
     /**
-     * Verify signature.
+     * Create signature.
      */
-    final public function verify(array $data, string $hash): bool
+    final public function create(array $data): string
     {
         $keys = [];
 
         foreach ($this->attributes as $attribute) {
             \array_push($keys, $attribute.($data[$attribute] ?? ''));
         }
 
-        $compared = \hash_hmac('sha256', \implode('|', $keys), $this->key);
+        return \hash_hmac('sha256', \implode('|', $keys), $this->key);
+    }
 
-        return \hash_equals($compared, $hash);
+    /**
+     * Verify signature.
+     */
+    final public function verify(array $data, string $hash): bool
+    {
+        return \hash_equals($this->create($data), $hash);
     }
 }