Bump org.spockframework:spock-core

Bumps [org.spockframework:spock-core](https://github.com/spockframework/spock) from 2.4-M2-groovy-4.0 to 2.4-M4-groovy-4.0.
- [Release notes](https://github.com/spockframework/spock/releases)
- [Changelog](https://github.com/spockframework/spock/blob/master/docs/release_notes.adoc)
- [Commits](https://github.com/spockframework/spock/commits)

---
updated-dependencies:
- dependency-name: org.spockframework:spock-core
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

build.gradle

@@ -87,7 +87,7 @@ subprojects {
 
         testCompileOnly 'org.projectlombok:lombok:1.18.32'
         testImplementation 'org.apache.groovy:groovy:4.0.20'
-        testImplementation 'org.spockframework:spock-core:2.4-M2-groovy-4.0'
+        testImplementation 'org.spockframework:spock-core:2.4-M4-groovy-4.0'
         testRuntimeOnly "net.bytebuddy:byte-buddy:1.14.12"
         testAnnotationProcessor 'org.projectlombok:lombok:1.18.32'