Update munit-scalacheck to 1.0.0-RC1 in main

Author: http4s-steward[bot]

build.sbt

@@ -13,7 +13,7 @@ lazy val root = project.in(file(".")).aggregate(scalaXml2).enablePlugins(NoPubli
 val http4sVersion = "1.0.0-M39"
 val scalacheckXmlVersion = "0.1.0"
 val scalaXmlVersion = "2.1.0"
-val munitVersion = "1.0.0-M11"
+val munitVersion = "1.0.0-RC1"
 val munitCatsEffectVersion = "2.0.0-M3"
 
 lazy val scalaXml2 = project