Merge branch 'retro-kickoff' into 'master'

Update PROCESS.md to point to retro and kickoff info

See merge request !14059

PROCESS.md

@@ -199,26 +199,8 @@ available in the package repositories.
 
 ## Release retrospective and kickoff
 
-### Retrospective
-
-After each release, we have a retrospective call where we discuss what went well,
-what went wrong, and what we can improve for the next release. The
-[retrospective notes] are public and you are invited to comment on them.
-If you're interested, you can even join the
-[retrospective call][retro-kickoff-call], on the first working day after the
-22nd at 6pm CET / 9am PST.
-
-### Kickoff
-
-Before working on the next release, we have a
-kickoff call to explain what we expect to ship in the next release. The
-[kickoff notes] are public and you are invited to comment on them.
-If you're interested, you can even join the [kickoff call][retro-kickoff-call],
-on the first working day after the 7th at 6pm CET / 9am PST..
-
-[retrospective notes]: https://docs.google.com/document/d/1nEkM_7Dj4bT21GJy0Ut3By76FZqCfLBmFQNVThmW2TY/edit?usp=sharing
-[kickoff notes]: https://docs.google.com/document/d/1ElPkZ90A8ey_iOkTvUs_ByMlwKK6NAB2VOK5835wYK0/edit?usp=sharing
-[retro-kickoff-call]: https://gitlab.zoom.us/j/918821206
+- [Retrospective](https://about.gitlab.com/handbook/engineering/workflow/#retrospective)
+- [Kickoff](https://about.gitlab.com/handbook/engineering/workflow/#kickoff)
 
 ## Copy & paste responses