Update lang/crystal to 0.28.0 and devel/shards to 0.9.0

Release notes: https://github.com/crystal-lang/crystal/releases/tag/0.28.0

https://github.com/crystal-lang/shards/releases/tag/v0.9.0

PR: 236969
Submitted by: Greg V<greg@unrelenting.technology> (maintainer)