Documentation: add step to bump version of Cilium used in upgrade tests
Documentation: add step to bump version of Cilium used in upgrade tests

As part of a release, after the release is announced, upgrade the version of
Cilium used in the CI upgrade tests. This ensures that the CI tests do not lag
behind in testing upgrade from the most recently released version of Cilium to
HEAD.

Signed-off by: Ian Vernon <ian@cilium.io>

cilium/cilium,scanf/cilium,tgraf/cilium,scanf/cilium,cilium/cilium,tgraf/cilium,tklauser/cilium,tklauser/cilium,tgraf/cilium,tgraf/cilium,scanf/cilium,scanf/cilium,scanf/cilium,tgraf/cilium,cilium/cilium,scanf/cilium,michi-covalent/cilium,cilium/cilium,michi-covalent/cilium,tgraf/cilium,tklauser/cilium,cilium-team/cilium,michi-covalent/cilium,michi-covalent/cilium,cilium-team/cilium,scanf/cilium,tklauser/cilium,cilium/cilium,michi-covalent/cilium,tklauser/cilium