fix(theming): make cache buster depend on the app version

Signed-off-by: Richard Steinmetz <richard@steinmetz.cloud>

Author: st3iny

apps/theming/lib/Util.php

@@ -311,12 +311,13 @@ public function getCacheBuster(): string {
 		if (!is_null($user)) {
 			$userId = $user->getUID();
 		}
+		$themingAppVersion = $this->appManager->getAppVersion('theming');
 		$userCacheBuster = '';
 		if ($userId) {
 			$userCacheBusterValue = (int)$this->config->getUserValue($userId, 'theming', 'userCacheBuster', '0');
 			$userCacheBuster = $userId . '_' . $userCacheBusterValue;
 		}
 		$systemCacheBuster = $this->config->getAppValue('theming', 'cachebuster', '0');
-		return substr(sha1($userCacheBuster . $systemCacheBuster), 0, 8);
+		return substr(sha1($themingAppVersion . $userCacheBuster . $systemCacheBuster), 0, 8);
 	}
 }