I would like to deploy a github project to a launchpad PPA repository so as to build snapshots of the project as debian packages.
For this I plan to run a github actions workflow on every commit which would create the debian source package (add the debian dir from another source and do a few other stuff on the package) and run backportpackage to prepare and publish it to launchpad. Launchpad's buildd bot would then build the binary packages and publish them on the PPA.
Note that the project on github doesn't ship the "debian" folder. It is taken from another source and added to the package in the github workflow with some changes made in the github job.
However if I understand correctly, the launchpad repo requires me to sign the package that is uploaded to it (or is it possible to do it unsigned?) This would require me to store the public & private GPG key used to sign the package on github.
I searched the github doc but 'account GPG key' doesn't seem to be the solution, and 'deploy keys' aren't either.
How could I solve the problem in a secure way? Or is there another way to achieve the same?