fixed problem with buildDescription
added an entry to the release notes
Update docs to reflect working monkey-patch method

Monkey-patching changed post https://github.com/jenkinsci/job-dsl-plugin/commit/3bf55f83e1087f2f2ca945d353e869884178cf66
and you need to `use(common) { job { ... } }` now.
[JENKINS-22857]: DSL for Workspace Cleanup Plugin post build action
- Fixed pull request comments, i.e. line indent, added default parameter for boolean, added unit tests

[JENKINS-22857]: DSL for Workspace Cleanup Plugin post build action
- Fixed pull request comments, i.e. line indent, added default parameter for boolean, added unit tests