How to customize the http.client?

[Herve-M]

Is there any way to customize the client?

I see azuredevops/client_options.go and azuredevops/client.go which seems to support it but not azuredevops/connection.go.

[Herve-M]

Seems to be related to #122

[peterdeme]

@nechvatalp can we please move on with #122 - we needed to fork this library because this PR's been open for 2 years...