.github: add release workflow and packaging support

[ozan956]

No description provided.

[pamolloy]

Can you compare your package to https://packages.debian.org/sid/amd64/openocd/filelist in https://packages.debian.org/sid/openocd?

[ozan956]

I updated the workflow to build on Ubuntu 20.04 so we don't break compatibility on older systems(as old as 20.04) or non-Ubuntu distros (since this only about supported version of the glibc). This makes the any-distro setting on Cloudsmith actually valid (this was the common practice so we can also assign a version based one as well) Does this logic make sense @pamolloy?

So i think at the end there are two options:

1- Build on an older base as we did. This creates a kind of portable binary (linking against glibc 2.31) that runs on almost everything. This allows us to use the any-distro label.

2- We would keep the build environment new, but we would have to compile separate artifacts for every distribution version we want to support and upload them separately (since the path / tag for cloudsmith gonna depend on that).