docs: update `CODEOWNERS` feature release instructions
docs: update `CODEOWNERS` feature release instructions

Documenting the general strategy should be more resistant to changes
over time than storing a snippet that folks might copy/paste by mistake
without looking at the current file from `master`.

Signed-off-by: Nicolas Busseneau <418d940643b1975d62234ee01246ad4b58904184@isovalent.com>

cilium/cilium,cilium/cilium,michi-covalent/cilium,michi-covalent/cilium,michi-covalent/cilium,michi-covalent/cilium,michi-covalent/cilium,cilium/cilium,cilium/cilium,cilium/cilium