owngrade org.ajoberstar.grgit to 4.0.2 for JVM

It looks like something has been changed in the transitive dependencies of the plugin:
```
org/eclipse/jgit/storage/file/FileRepositoryBuilder has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0
```

* Downgrade to see and effect without moving to Java 11

build.gradle

@@ -14,7 +14,7 @@ buildscript {
 plugins {
 	id 'org.sonarqube' version '2.8'
 	id 'io.spring.nohttp' version '0.0.10' apply false
-	id 'org.ajoberstar.grgit' version '4.1.0'
+	id 'org.ajoberstar.grgit' version '4.0.2'
 	id 'io.spring.dependency-management' version '1.0.11.RELEASE'
 	id 'com.jfrog.artifactory' version '4.24.20' apply false
 	id 'org.jetbrains.dokka' version '0.10.1'