Fixed minor bug with urlfriendly initials that was not covered by tests.

Author: LasseRafn

src/Initials.php

@@ -147,7 +147,7 @@ private function convertToUrlFriendlyString( $string ): string
 	{
 		foreach ( static::charsArray() as $key => $val )
 		{
-			$string = str_replace( $val, $key, $string );
+			$string = str_replace( $val, mb_substr($key, 0, 1), $string );
 		}
 
 		return preg_replace( '/[^\x20-\x7E]/u', '', $string );

tests/InitialGenerationTest.php

@@ -51,5 +51,10 @@ public function testInitialsAreGeneratedFromFullname()
 
 		$this->assertEquals( 'MCA', $avatar->getUrlfriendlyInitials() );
 		$this->assertEquals( 3, strlen( $avatar->getUrlfriendlyInitials() ) );
+
+		$avatar->length( 3 )->name( 'Jens Ølsted' );
+
+		$this->assertEquals( 'JOL', $avatar->getUrlfriendlyInitials() );
+		$this->assertEquals( 3, strlen( $avatar->getUrlfriendlyInitials() ) );
 	}
 }