Update scalacheck to 1.15.4 (#334)

build.sbt

@@ -8,7 +8,7 @@ lazy val versionOf = new {
   val kindProjector = "0.11.3"
   val log4cats      = "1.3.0"
   val log4s         = "1.9.0"
-  val scalaCheck    = "1.15.3"
+  val scalaCheck    = "1.15.4"
   val scalaTest     = "3.2.8"
   val zio           = "1.0.7"
   val scribe        = "3.5.4"