FR: add --label to jj gerrit upload #8253
Description
Is your feature request related to a problem? Please describe.
On a gerrit instance I use, we have a bot that autosubmit CLs that pass all tests and are labeled with Autosubmit+1. You can easily achieve that using the following git invocation: git push origin HEAD:refs/for/main -o l=Autosubmit+1
Describe the solution you'd like
That would be really cool to be able to do jj gerrit upload -r <changeset> --label label1 --label label2 or jj gerrit upload -r <changeset> --labels label1,label2 depending on what people prefer.
That would be great if the labels could be persisted across revision upload. Like if I do jj gerrit upload -r r --label demo-label and I want to upload a second revision of the CL I could simply do jj gerrit upload -r r and the label(s) are preserved.
Describe alternatives you've considered
I'm just gonna fallback to uploading using git or setting the label manually in each CL, which works, but isn't great.