update GitLab lib (#325)

Co-authored-by: Thomas Michael <thomas.michael@cloudogu.com>

Author: ThomasMichael1811

pom.xml

@@ -309,7 +309,7 @@
     <dependency>
       <groupId>org.gitlab4j</groupId>
       <artifactId>gitlab4j-api</artifactId>
-      <version>6.0.0-rc.8</version>
+      <version>6.2.0</version>
     </dependency>
 
     <dependency>