buildProjectFileTranslation doesn't reset If-None-Match header on consecutive calls

[erickskrauch]

The title 👆

This can be easily fixed by adding here an else block and calling the removeHeader() method:

crowdin-api-client-php/src/CrowdinApiClient/Api/TranslationApi.php

Lines 103 to 105 in 3a37c3f

	if ($ifNoneMatch) {
	$this->setHeader('If-None-Match', $ifNoneMatch);
	}

Also, I would suggest changing the type of $ifNoneMatch from string to ?string since it accepts a null value.