Support for subtask parent in Jira Cloud for Sheets

Currently the add-on does not return the parent issue for a subtask.

The proposed solution is to return the "parent" object, as per the advanced fields documentation : https://confluence.atlassian.com/jirasoftwarecloud/advanced-searching-fields-reference-764478339.html 

Which can be used like this:

=JIRA("project=TEST", "key, summary, parent.key, parent.summary")