Releasing a new version

We will use the v0.15.8 release #202 as an example of how to release a new greenboot version:

Fork the repo and create a new branch for the new release:

gh repo fork fedora-iot/greenboot --clone --remote
git pull upstream main
git checkout -b prepare-v0.15.8

Update the greenboot.spec file and set the new version: rpmdev-bumpspec -n 0.15.8 greenboot.spec
Update anything required for the new RPM
Update the changelog section of the spec file

Commit all the changes and create a PR (see #738 with all the changes described above):

git add greenboot.spec # add anything else needed
git commit -s -m "chore: bump for 0.15.8 release" -m "Prepare for the 0.15.8 release."
gh pr create

Once all the tests pass and the PR is merged, tag and sign the release:
```
git tag -a -s v0.15.8
git push upstream v0.15.8
```
Using the webui, open the Releases page and click the "Draft a new release" button in the middle of the page. From there you can choose the v0.15.8 tag you created in the previous step.
- Use the version as the "Release title" and keep the format i.e. "v0.15.8".
- In the description add in any release notes or click "Generate release notes". When satisfied, click the "Save draft" or "Publish release" button at the bottom of the page.

Provide feedback