Update coursier, coursier-jvm to 2.1.21

Author: scala-center-steward[bot]

project/Dependencies.scala

@@ -8,7 +8,7 @@ object Dependencies {
   val scala31Plus = scalaEnvVersion.filter(isScala31Plus).getOrElse("3.3.4")
   val scala34Plus = scalaEnvVersion.filter(isScala34Plus).getOrElse("3.5.2")
   val asmVersion = "9.7.1"
-  val coursierVersion = "2.1.20"
+  val coursierVersion = "2.1.21"
 
   def isScala212(version: String): Boolean = version.startsWith("2.12")
   def isScala213(version: String): Boolean = version.startsWith("2.13")