build: Update flyway-core, flyway-mysql from 9.20.1 to 9.21.0

Author: j5ik2o-bot[bot]

build.sbt

@@ -161,8 +161,8 @@ val `docker-controller-scala-flyway` = (project in file("docker-controller-scala
   .settings(
     name := "docker-controller-scala-flyway",
     libraryDependencies ++= Seq(
-      "org.flywaydb"      % "flyway-core"  % "9.20.1",
-      "org.flywaydb"      % "flyway-mysql" % "9.20.1",
+      "org.flywaydb"      % "flyway-core"  % "9.21.0",
+      "org.flywaydb"      % "flyway-mysql" % "9.21.0",
       scalatest.scalatest % Test,
       logback.classic     % Test
     )