New upstream version + misc improvements

Hi,

This MR brings go-pinentry up to the last upstream version. It also provide packaging improvements, some of them may be controversial (e.g. watch file removal).

I'm marking this request as draft because the two packages in the archive that depend on go-pinentry ftbfs with this new version:

• tkey-ssh-agent (tkey-ssh-agent!1 (merged))
• yubikey-agent (yubikey-agent!1 (merged))

I will send MRs to fix those build failures.