Release checklist: the release manager should wait between step 13 an…

…d step 14 (#48942)

Makefile

@@ -152,7 +152,7 @@ release-candidate: release testall
  @echo 10. Follow packaging instructions in doc/build/distributing.md to create binary packages for all platforms
  @echo 11. Upload to AWS, update https://julialang.org/downloads and http:https://status.julialang.org/stable links
  @echo 12. Update checksums on AWS for tarball and packaged binaries
- @echo 13. Update versions.json
+ @echo 13. Update versions.json. Wait at least 60 minutes before proceeding to step 14.
  @echo 14. Push to Juliaup (https://github.com/JuliaLang/juliaup/wiki/Adding-a-Julia-version)
  @echo 15. Announce on mailing lists
  @echo 16. Change master to release-0.X in base/version.jl and base/version_git.sh as in 4cb1e20