Bump spock-core from 1.3-groovy-2.5 to 2.3-groovy-4.0

Bumps spock-core from 1.3-groovy-2.5 to 2.3-groovy-4.0.

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

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

Author: dependabot[bot]

build.gradle

@@ -18,7 +18,7 @@ dependencies {
 
     compile 'org.hibernate:hibernate-entitymanager:5.6.15.Final'
 
-    testCompile 'org.spockframework:spock-core:1.3-groovy-2.5'
+    testCompile 'org.spockframework:spock-core:2.3-groovy-4.0'
     testCompile 'junit:junit:4.13.2'
 
     runtime 'org.glassfish:javax.json:1.1.4'