Make logrotate run as git user for source installations

Signed-off-by: Balasankar "Balu" C <balasankarc@autistici.org>

changelogs/unreleased/fix-logrotate-su-parameter.yml

+---
+title: Make logrotate run as git user for source installations
+merge_request: 35519
+author:
+type: security

lib/support/logrotate/gitlab

@@ -2,6 +2,7 @@
 # based on: http://stackoverflow.com/a/4883967
 
 /home/git/gitlab/log/*.log {
+    su git git
     daily
     missingok
     rotate 90
@@ -11,6 +12,7 @@
 }
 
 /home/git/gitlab-shell/gitlab-shell.log {
+    su git git
     daily
     missingok
     rotate 90