Add EmailInterface.php

Signed-off-by: Nathanael Esayeas <nathanael.esayeas@protonmail.com>

src/Interface/Git/Commit/Author/EmailInterface.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Ghostwriter\Arm\Interface\Git\Commit\Author;
+
+use Ghostwriter\Arm\Interface\StringableInterface;
+
+interface EmailInterface extends StringableInterface
+{
+    public static function new(string $email): self;
+}