Add Gitlab version to Snowplow tracking events

Problem to solve

We started to track structured events with Snowplow. In the future, we will add/remove/change events or may possible to track https://github.com/snowplow/snowplow/wiki/2-Specific-event-tracking-with-the-Javascript-tracker#381-trackselfdescribingevent as well.

If we try to query the Snowplow dataset will be hard to know exactly which period we should consider for a given event. It's much straightforward to filter by Gitlab versions.

Proposal

Would be great if we could add Gitlab's version to every tracking events via Snowplow JS tracker context

Links / references