Enable semantic versioning through GitHub app

[gabenegron]

Current pipeline uses personal access token to enable semantic versioning. Since GitHub doesn't have the option of using a service/admin account, the most feasible option that allows us to get away from using a personal access token is using a GitHub app.

Acceptance Criteria

• Pipeline is able to successfully continue to perform semantic versioning of our application, without the use of a personal access token

[chrisba11]

Here is my PR for this: #195

I used the wrong ticket number in my branch name, so I wanted to link it here so there's a trail to follow.

[chrisba11]

This has been completed in PR #272. Leaving open because I am using the same ticket number to handle switching all uses of Sascha's PAT to using the actions-helper GH App token.