Create new milestone github action

[CalvinWilkinson]

Complete The Item Below

• I have updated the title without removing the 🚧 emoji.

Description

Create a new custom github action that creates a new milestone.

The GitHub action should have the following inputs:

1. repo-owner
2. repo-name
3. milestone-name
4. github-token
5. deno-version

A good example to go off of is the close-milestone custom github action. Like all of the other custom github actions, it will use deno and a deno script to perform the work.

Before creating a new milestone, check whether it already exists. Fail the action if the milestone already exists.

Acceptance Criteria

The items to complete to satisfy the Definition of Done.

• All the unit tests have been executed and passed locally after PR work is complete. (Why? Refer to 'Additional Information' below.)
• Created a new custom GitHub action for creating milestones.
• Defined the following inputs for the action:
  • repo-owner
  • repo-name
  • milestone-name
  • github-token
  • deno-version
• Implemented the core logic using Deno and a Deno script, following the pattern of the close-milestone action.
• Added a check to verify if the milestone already exists before creation.
• Configured the action to fail if the milestone already exists.

ToDo Items

The items to complete to satisfy the Definition of Done.

• Add a priority label to the issue. Refer to the Priority Type Labels section below.
• Link the issue to the correct milestone (if applicable).

Code of Conduct

• I agree to follow this project's Code of Conduct.