:wrench: changed $dataModeOverride default value to '', fix for https://github.com/chillerlan/php-qrcode/issues/97

src/QROptionsTrait.php

@@ -77,8 +77,9 @@ trait QROptionsTrait{
 	 * valid modes are: Number, AlphaNum, Kanji, Byte (case insensitive)
 	 *
 	 * @see https://github.com/chillerlan/php-qrcode/issues/39
+     * @see https://github.com/chillerlan/php-qrcode/issues/97 (changed default value to '')
 	 */
-	protected ?string $dataModeOverride = null;
+	protected string $dataModeOverride = '';
 
 	/**
 	 * The output type