Merge branch 'docs/update-time-tracking-release-info' into 'master'

Change time tracking units feature release version

See merge request gitlab-org/gitlab-ce!30771

doc/workflow/time_tracking.md

@@ -75,7 +75,7 @@ Default conversion rates are 1mo = 4w, 1w = 5d and 1d = 8h.
 
 ### Limit displayed units to hours
 
-> Introduced in GitLab 12.0.
+> Introduced in GitLab 12.1.
 
 The display of time units can be limited to hours through the option in **Admin Area > Settings > Preferences** under 'Localization'.