feat: git https credentials for template leak into final repo

Is your feature request related to a problem? Please describe. Currently, copier does not support Git HTTPS template URLs with included credentials. At least not without leaking these credentials into the .copier-answers.yml file of the target repo.

I.e., commands like this are not a great idea, but there exists no workaround:

copier copy https://myuser:[e-mail]/repo.git .

Describe the solution you’d like It would be great if credentials for cloning the template could be passed during runtime to copier (i.e. through env variables, cli arguments or separate secret files). For example with a command like:

copier copy \
    --template-clone-username myuser
    --template-clone-password secretpw
    https://myrepos.com/repo.git .

These credentials should then not be saved in the target repo - but instead a future user running copier update must supply his own credentials again.

[defreng]

ok 😂 then this ticket is basically about allowing something similar to the SSH usecase, but when SSH is not an option.

This may happen in many cases, such as:

• Git can’t be used over SSH because the port is not accessible (i.e. from a corporate network that only allows outgoing HTTP traffic via a proxy)
• When using machine authentication (for example GitLab personal access tokens or group deploy tokens), those mechanisms often only provide a username/token for HTTPS authentication

[pawamoy]

Or maybe Copier could detect when git is asking for credentials, and allow the user to input them. It would abort with an error if the force option (no-input option) is used.