Add auto-update workflow for newt

[joe2824]

This PR introduces a new GitHub Actions workflow to automatically update Newt to the newest version.
This reduces manual maintenance work for the repository.

Required Repository Changes:
For this workflow to run successfully, the repository settings must be updated. Please ensure the following:

1. Go to Settings > Actions > General.
2. Under Workflow permissions, check the box for Allow GitHub Actions to create and approve pull requests.

[Empathies]

This would make my PR (and the potential future ones) obsolete.
I like it 😄

[alexmoras]

Thanks for taking the time to submit this PR. There are a couple changes I think would be needed before we can merge. Mainly around the fact that the action doesn't have any awareness of the current version, and will create a new PR every time it runs, even if the version hasn't incremented.

[alexmoras]

v8 is the latest, so probably best we implement based on that.

[alexmoras]

Further to the above code review, we need to consider whether automatic version incrementing is appropriate. I appreciate I do not update the versions all that often, but at least we know the add-on is stable. If we allow the action to automatically merge PRs, we risk implementing a version of Newt which isn't compatible with the add-on configuration, without some human changes. This could break people's access to HA.

Also, this PR would not cause a new version of the add-on to be published. Another step would be needed to create a new GitHub Release, since this is what builds the new docker images.

I'm open to suggestions, just wanted to raise a few points of discussion. 😄

[joe2824]

Ah I messed it up :/

Further to the above code review, we need to consider whether automatic version incrementing is appropriate. I appreciate I do not update the versions all that often, but at least we know the add-on is stable.

Yes you are totally right. I added a function that checks for the latest stable release (15 day delay after minor release)
For example the current latest stable version would be 1.11.0

Also, this PR would not cause a new version of the add-on to be published. Another step would be needed to create a new GitHub Release, since this is what builds the new docker images.

I also change it to release and also trigger the build command
I'm not sure about the build. You mentioned that homeassistant have a new build process action #21.
I just copy and paste the action.