bug#60229: [NonGNU ELPA] Change elpher upstream URL from git:// to https://

[Stefan Kangas]

NonGNU ELPA is using this unencrypted URL for the `elpher' package's
upstream:

    git://thelambdalab.xyz/elpher.git

Could we change it to use https:// instead?  This is a good idea for all
the usual reasons (security, privacy, etc.).

I note that there is already a gitweb instance behind HTTPS here:

    https://thelambdalab.xyz/gitweb/index.cgi?p=elpher.git;a=summary

So perhaps exposing the git repository itself wouldn't be too much work.