feat(all): added github enterprise support and more!

[Bullrich]

This is a major rewrite of the application.

Let's first start with the features:

New features

• Whole app has been rewritten in Typescript
  • We now have types!
    • This makes it easies to mantain
• @octokit package has been updated
  • Now it supports GitHub Enterprise instances (the update was required for this)
• Unit test library has been added
• GitHub actions has been added to test the state of the code and of new PRs.
• GitHub actions has been added to generate changelogs with new release information.
• Head branch can now be changed (instead of always using master)

More technical change

• I moved the build system to download dependencies inside the Docker container
  • This means that it doesn't need to use node_modules anymore but does that on run time.
  • Codebase is incredible smaller now.
    • Almost 80.000 lines deleted.
• Everything is built using tsc and then optimized using ncc automatically on execution.
• When updating the @octokit dependency I saw that so many things changed that it was easier to rewrite the app in ts instead of trying to figure out the problem, that's why I took that approach.
• Fixed problem where the action would try to push the existing tag because it was checking against null and not undefined.

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I have created my own fork with these features: https://github.com/Bullrich/commit-autotag

This is currently working so you can try using that fork if you wish to see the behavior of my changes.