crystal: update to 0.31.1.

[sebmenard]

• Compilation was locally tested with both i686 and x86_64
• Package was locally installed on x86_64, crystal and shards work good
• Issue with multi-threading: it is not possible to compile programs with the -Dpreview_mt flag. As said in crystal: update to 0.31.0. #14688 a patch to gc is required for them to work, and we will eventually not bump this package until a new release which will contain this new feature.

Note to Crystal developers: If you really want to enable green threads support in the gc package, please use this patch and compile gc (I did it using xbps-src using the same revision and force reinstalled it: it works without issue). Good luck!