Update 2.13 release notes
Update 2.13 release notes

Update the JGit version.

Change-Id: Icd7781465935c4acad8b6d91aad66a2ea67a386b

qtproject/qtqa-gerrit,WANdisco/gerrit,gerrit-review/gerrit,gerrit-review/gerrit,WANdisco/gerrit,WANdisco/gerrit,WANdisco/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,qtproject/qtqa-gerrit,WANdisco/gerrit,GerritCodeReview/gerrit,gerrit-review/gerrit,WANdisco/gerrit,gerrit-review/gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,WANdisco/gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,gerrit-review/gerrit,qtproject/qtqa-gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,gerrit-review/gerrit,gerrit-review/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit