Update scalatest to 3.2.20

Author: scala-steward

build.sbt

@@ -51,7 +51,7 @@ val sharedSettings = Seq(
   ),
   libraryDependencies ++= Seq(
     "org.scalacheck" %% "scalacheck" % "1.15.2" % "test",
-    "org.scalatest" %% "scalatest" % "3.2.15" % "test",
+    "org.scalatest" %% "scalatest" % "3.2.20" % "test",
     "org.scalatestplus" %% "scalatestplus-scalacheck" % "3.1.0.0-RC2" % "test",
     "com.esotericsoftware" % "kryo-shaded" % kryoVersion
   ),