**If this is a source code change then start here.**
In the `main` branch:
- Update the version number in the source code for the command line usage message.
- Add a tag matching the version number in the command line usage message.
- Commit and push.
In the `debian/bullseye` branch:
- Import the changes from the `main` branch.
Change `<version>` to the version number of the `main` branch:
`gbp import-ref main -u <version> --upstream-tag='%(version)s' --debian-branch=debian/bullseye`
**If this is a packaging change then start here.**
- Update the changelog.
Change `<version>` to the version number of the `main` branch. If this is a source code change then change `<n>` to 1. If this is a packaging change then change `<n>` to the previous `n` plus 1.
