Update dependency useSpock to v2.4-M6-groovy-3.0

Author: renovate[bot]

build-logic/base/base.gradle

@@ -19,7 +19,7 @@ dependencies {
 testing {
   suites {
     test {
-      useSpock('2.4-M5-groovy-3.0')
+      useSpock('2.4-M6-groovy-3.0')
     }
   }
 }