Bump org.jenkins-ci.main:jenkins-core from 2.563 to 2.568 in /ui-tests

Bumps [org.jenkins-ci.main:jenkins-core](https://github.com/jenkinsci/jenkins) from 2.563 to 2.568.
- [Release notes](https://github.com/jenkinsci/jenkins/releases)
- [Commits](jenkinsci/jenkins@jenkins-2.563...jenkins-2.568)

---
updated-dependencies:
- dependency-name: org.jenkins-ci.main:jenkins-core
  dependency-version: '2.568'
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

ui-tests/pom.xml

@@ -16,7 +16,7 @@
   <name>UI Tests of Git Forensics Plugin</name>
 
   <properties>
-    <jenkins.version>2.563</jenkins.version>
+    <jenkins.version>2.568</jenkins.version>
     <hpi-plugin.version>3.1829.v1595655f4b_49</hpi-plugin.version>
     <json-smart.version>2.3</json-smart.version>
     <json-unit-assertj.version>5.1.1</json-unit-assertj.version>