Features/gitlab custom cert

[fdbastionamio]

Closes #49

This adds an entry in the gitlab config section called ssl-cert where users can specify the path to the PEM certificate of their gitlab instance if it is using a self-signed certificate.

example configuration:

# socket address for the SSH server to listen on
listen-address = "[::]:2222"

# directory in which the generated private keys for the server
# should be stored
state-directory = "/var/lib/gitlab-cargo-shim/keys"

[gitlab]
# the base url of the gitlab instance
uri = "https://my.gitlab.internal"
ssl-cert = "/etc/ssl/certs/my.gitlab.internal.pem"

# a personal access token of an admin with permission to `sudo` as other
# users and create impersonation tokens. `sudo` is used to fetch all the
# packages the user can access, and the impersonation token is returned
# to the user to download packages
admin-token = "foobar"

[fdbastionamio]

Apologies - I forgot to run rustfmt and use the user-supplied ssl cert for non-admin requests

[w4]

Thanks for the contribution!

[w4]

Would you mind fixing the clippy failure please? Other than that, all looks good to me.

[fdbastionamio]

Hi, this should work now