Twoliter 0.12.0 Schema Update - Action Required

With the release of Twoliter 0.12.0, we have introduced a new version bump to the schema of `Twoliter.toml` and `Twoliter.lock`. For everyone who wants to update to Twoliter 0.12.0 you will need to run a `twoliter update` to update your Twoliter.lock file automatically to the new schema-version 2. For Twoliter.toml the existing schema-version 1 is fully backwards compatibility.

### New Field: **project-vendor**
With schema-version 2 we have introduced a new required field called **project-vendor**. This field is now used to set the VENDOR_NAME in the os-release (/etc/os-release). This allows our OOTB variants to change the default from 'Bottlerocket' to their own name.

Start with the Twoliter.toml and Twoliter.lock schema references and the `twoliter update` command described in the issue. Verify how schema-version 2 and the required project-vendor field affect migration and the generated /etc/os-release VENDOR_NAME, but the issue does not identify a file, test, or concrete repository change.

Written by the indexing model from the issue text.