Consider updating lerna and removing dependency to`mocha-jenkins-reporter`

[tortmayr]

All dependabot allerts in the main glsp repo are related to either lerna or mocha-jenkins-reporter. For lerna we could update to the new 5.x version which should resolve most of the alerts. However, this also means we have to use a more restrictive node version range ("^14.19.3 || >=16.0.0")

The mocha-jenkins-reporter only has irregular releases so we can't expect a new version there soon. Maybe we should drop the dependency altogether.