Subsonic API: added version in album responses

SUBSONIC.md

@@ -36,6 +36,7 @@ The following extra fields are implemented:
   * `recordLabels`
   * `releaseTypes`
   * `userRating`
+  * `version`
 * `Child` response:
   * `albumArtists`
   * `artists`

src/libs/subsonic/impl/responses/Album.cpp

@@ -145,6 +145,7 @@ namespace lms::api::subsonic
             return albumNode;
 
         // OpenSubsonic specific fields (must always be set)
+        albumNode.setAttribute("version", release->getComment());
         albumNode.setAttribute("sortName", release->getSortName());
         albumNode.setAttribute("mediaType", "album");