running command `cargo dist generate` in a branch different than `main` not updating github workflow

Dear cargo dist team,

I am trying to update the github runner in my giuthub pipeline generated by cargo dist.
I changed the github runner to `ubuntu-22.04` here https://github.com/eth-cscs/manta/blob/1.5/dist-workspace.toml under branch `1.5`

Then I ran `cargo dist generate` and `cargo dist init`

Then I check the github pipeline under `.github/workflows/release.yml` but the github runner still points to `ubuntu-20.04`

Any idea why? I suspect it is because I am not in main branch

Reproduce from the reported branch using dist-workspace.toml, then run `cargo dist generate` and `cargo dist init` and inspect `.github/workflows/release.yml`. Compare the generated workflow with the `ubuntu-22.04` setting and determine whether branch context affects generation; done means the documented or corrected behavior is verified for a non-main branch.

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