Bump org.spockframework:spock-core from 2.3-groovy-3.0 to 2.4-groovy-5.0

Bumps [org.spockframework:spock-core](https://github.com/spockframework/spock) from 2.3-groovy-3.0 to 2.4-groovy-5.0.
- [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-version: 2.4-groovy-5.0
  dependency-type: direct:production
...

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

Author: dependabot[bot]

ocpp-v1_6-test/build.gradle

@@ -12,7 +12,7 @@ dependencies {
 
     testCompile 'junit:junit:4.13.2'
     testCompile 'org.codehaus.groovy:groovy-all:3.0.25'
-    testCompile 'org.spockframework:spock-core:2.3-groovy-3.0'
+    testCompile 'org.spockframework:spock-core:2.4-groovy-5.0'
     testCompile 'org.hamcrest:hamcrest-core:3.0'
     testCompile 'ch.qos.logback:logback-core:1.3.16'
     testCompile 'ch.qos.logback:logback-classic:1.3.16'