Minor gradle cleanups (#1197)

* Update to Gradle 6.6

* Remove stdlib deps

No longer necessary in Kotlin 1.4.0

* Gradle 6.6.1

build.gradle.kts

@@ -82,8 +82,4 @@ subprojects {
       }
     }
   }
-
-  pluginManager.withPlugin("org.jetbrains.kotlin.jvm") {
-    dependencies.add("api", Dependencies.Kotlin.stdlib)
-  }
 }