Remove minimum Gradle version from readme

version is controlled by the wrapper

Author: big-guy

README.adoc

@@ -16,7 +16,6 @@ To engage in the development of the plugin, follow the minimum requirements show
 |==========================
 |Tool    |Minimum Version
 |JDK     |Oracle JDK or OpenJDK 8.x, anything higher won't work with Scala 2.11
-|Gradle  |5.1 or higher
 |IDE     |IntelliJ 2018.2 or higher
 |==========================