Add release tags & sign commits

[ejose19]

It would be great if this had release tags, so when building one can use an specific tag instead of master.

Also, to retain the good practices of verifying signatures, commits should be signed so users can use git verify-tag before starting to build.

[dagurval]

Thanks for the suggestion. I'll look into using GPG signed tags for future releases.

There exist release branches you could use instead of master, like v3.0.0, but as you say, these are not signed.