[ ci ] bring racket builds back
[ ci ] bring racket builds back

A new environment seems to have solved our issue.
Cf. actions/virtual-environments#3774

mmhelloworld/idris-jvm,mmhelloworld/idris-jvm,mmhelloworld/idris-jvm,mmhelloworld/idris-jvm,mmhelloworld/idris-jvm,mmhelloworld/idris-jvm