Update RELEASE_PROCESS.md (#3910)
Update RELEASE_PROCESS.md (#3910)

Add missing ubuntu 21.04 and rocky 8 release artifacts to list of artifacts to expect.
ponylang/ponyc,jemc/ponyc,sgebbie/ponyc,dipinhora/ponyc,sgebbie/ponyc,dipinhora/ponyc,jemc/ponyc,sgebbie/ponyc,jemc/ponyc,sgebbie/ponyc,ponylang/ponyc,ponylang/ponyc,sgebbie/ponyc,dipinhora/ponyc