gbp:error: upstream/4.4.0+ds1 is not a valid treeish

[Nico Schlömer <nico.schloemer@gmail.com>]

Hi everyone,

I'm trying to update gmsh [1], but the tests on salsa report
```
gbp:error: upstream/4.4.0+ds1 is not a valid treeish
```
See [2]. I have no idea why this comes up.

Any hints?

Cheers,
Nico

[1] https://tracker.debian.org/pkg/gmsh
[2] https://salsa.debian.org/science-team/gmsh/-/jobs/221777