Removing CredHub dependency from buildscript

Since we deleted the credhub-security module as part of 135e3496d1, we don't need this dependency in the buildscript anymore

build.gradle

@@ -23,7 +23,6 @@ buildscript {
 		commonsTextVersion = "1.10.0"
 		immutablesVersion = "2.9.3"
 		openServiceBrokerVersion = "4.0.0"
-		springCredhubVersion = "3.0.0"
 		springFrameworkVersion = "6.0.0"
 		wiremockVersion = "2.35.0"
 	}