Fix version dump and updates

In commit 254b71ed the format of the intermediate files was changed to JSON to improve performance and save resources. With this change the logic to dump version information was adapted, but unfortunately not all the cases were covered, causing version to be dumped as null. As a consequence, the checks for updates also fail.

Fix the dumping of version information by using string.

https://phabricator.apertis.org/T10163

Signed-off-by: Walter Lozano walter.lozano@collabora.com