Bump dependencies and delete moultingyaml (#4063)

* scalatest: 3.2.14 => 3.2.18
* scalacheck-1-16:3.2.14.0 => scalacheck-1-18:3.2.18.0
* json4s-native: 4.0.6 => 4.0.7
* commons-text: 1.10.0 => 1.12.0
* os-lib: 0.9.1 => 0.10.0
* upickle: 3.1.0 => 3.3.0

* Delete moultingyaml, it has been unused for a long time
* Make Mill versions consistent with SBT versions