remote_package_name.git2r_remote uses (some) credentials

[rnorberg]

Related to #632 and #625. Now, when trying to download a package's DESCRIPTION file from a repo that requires authentication, some types of credentials (git2r::cred_user_pass, git2r::cred_env, and git2r::cred_token) are passed to the (internal) download function.

[rnorberg]

Related to #632 and #625.

[statnmap]

@rnorberg thank you for this correction that saves me. There is a missing parenthesis, but I can validate that this works correctly after that.
You can test it with this reprex. The package {hello.seb} in private on gitlab.com. The credentials were created only for the purpose of this package, so that you can use it too.

if (!requireNamespace("git2r")) {install.packages("git2r")}
# Specific credentials for this private project
options(remotes.git_credentials = 
          git2r::cred_user_pass(username = "gitlab+deploy-token-521061", 
                                password = "Nbebu3FGGtZ6VMbLx23K"))
repo_url <- 'https://gitlab.com/statnmap/hello.seb'

# Does not work with remotes 1.4, but OK with 1.3
remotes::install_git(url = repo_url, git = "git2r")

[jimhester]