docs: Update release process against template
docs: Update release process against template

Some recent template changes have not yet been propagated into the docs,
update the docs with the latest steps.

Signed-off-by: Joe Stringer <16a9a54ddf4259952e3c118c763138e83693d7fd@cilium.io>

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