[3.20] community/crystal: upgrade to 1.12.2
https://github.com/crystal-lang/crystal/releases/tag/1.12.2
Backport of !66968 (merged) as this contains a compatibility fix for gc 8.2.6
https://github.com/crystal-lang/crystal/releases/tag/1.12.2
Backport of !66968 (merged) as this contains a compatibility fix for gc 8.2.6