fix: clone when user use ssh

[AlexD10S]

A user reported an issue when generating the parachain:

~/github/pop
❯ pop new parachain Demo
┌   Pop CLI : Generating "Demo" using Base Parachain Template!
│
Error: authentication required but no callback set; class=Ssh (23); code=Auth (-16)

It seem our current code for cloning a repository was throwing an error, fixed using RepoBuilder. Based on this example: https://docs.rs/git2/0.13.1/git2/build/struct.RepoBuilder.html#example

After that fix user was having another issue:

~/github/pop
❯ pop new parachain my-app
┌   Pop CLI : Generating "my-app" using Base Parachain Template!

Error: remote rejected authentication: Failed getting response; class=Ssh (23); code=Auth (-16)

With seems is an issue authenticating for the SSH clone. Fixed using the library: https://crates.io/crates/git2_credentials

Also I removed Repository::init(target)?; from instantiate_base_template. After this PR #65 where we where the git init repo was introduced it gets duplicated.

How to replicate the issue:
This is tricky, I wasn't able to get same issue as the user, but if you change your way to clone, to use SSH you will see an error too in current main:
git config --global url."[email protected]:".insteadOf "https://github.com/"
A guide on how to set up SSH cloning:
https://www.theserverside.com/blog/Coffee-Talk-Java-News-Stories-and-Opinions/github-clone-with-ssh-keys

[weezy20]

Great work @AlexD10S. Only mandating changes in the error handler for git2:Config. Rest looks good.

[weezy20]

TBF, I still do not understand how to replicate this issue because we are straight up asking git2 in pop to use https. I don't understand the point of this configuration:

git config --global url."[email protected]:".insteadOf "https://github.com/"

[AlexD10S]

TBF, I still do not understand how to replicate this issue because we are straight up asking git2 in pop to use https. I don't understand the point of this configuration:

Some people set up their git configuration to clone the repositories using SSH using insteadOf

Before this fixes you can try:

git config --global url."[email protected]:".insteadOf "https://github.com/"

And this will throw an error when try to clone, because even pop has https:: your git will go with the new configuration. See this issue: rust-lang/git2-rs#901