Add issue to milestone project

[Ryan089]

Summary

Adds issue to the appropriate milestone project when milestone is set.

Changes to Files

Nil changes, new code only.

Limitations

• This workflow is unidirectional. Although adding an issue to a milestone will trigger its insertion to the project board, removing it from a milestone will not automatically trigger its removal from the board.

Fixes

Contributes to #1112 by completing the following task:

• When a GitHub Milestone is added to an open issue, add the issue to the GH Project of the same name as the Milestone, in the 'backlog' column.

[cosmiccoincidence]

Lgtm

[cosmiccoincidence]

Tested it, works well!