Support for on-premises GitLab instances with no certification (http)

This is similar to https://gitlab.com/fatihacet/gitlab-vscode-extension/issues/26, but my GitLab instance is in the private LAN with no certification. The url is just like http://192.168.123.45:6789. When I try to set URL to Gitlab instance, it will show

Gitlab instance "http://" is not a valid URL

Any suggestions? Thanks!