version must be a string that php function version_compare work right (…

…#214)

ref: FreshRSS/FreshRSS#6155

generate.php

@@ -53,6 +53,7 @@
  }
  $directory = basename(dirname($metadataFile));
  $metadata['url'] = $gitRepository;
+ $metadata['version'] = strval($metadata['version']);
  $metadata['method'] = TYPE_GIT;
  $metadata['directory'] = ($directory === sha1($gitRepository)) ? '.' : $directory;
  $extensions[] = $metadata;