Add support for adding & removing labels when no longer stale (#468)

* Add support for adding & removing labels when no longer stale

* Add remove/addLabelsWhenUpdatedFromStale to relevant spec files. Modify arguments to remove ambiguity in 'labels' var & parameter

* Change parameters for clarity, let autoformat do its thing

* PR feedback: More useful logging when removing labels

* Wrap client calls in try catches

* Use Unstale in variable names

* Don't run add label logic under debug

* Add test for labels added to unstale issues

* PR Feedback: logging

* Update README

* Rename vars to labels-to-add/remove-when-unstale

* Apply doc suggestions from code review

Co-authored-by: Geoffrey Testelin <geoffrey.testelin@gmail.com>

* PR Feedback

Co-authored-by: Geoffrey Testelin <geoffrey.testelin@gmail.com>

src/classes/issue.spec.ts

@@ -55,7 +55,9 @@ describe('Issue', (): void => {
       exemptAllAssignees: false,
       exemptAllIssueAssignees: undefined,
       exemptAllPrAssignees: undefined,
-      enableStatistics: false
+      enableStatistics: false,
+      labelsToRemoveWhenUnstale: '',
+      labelsToAddWhenUnstale: ''
     };
     issueInterface = {
       title: 'dummy-title',