Updating commands doc to use https instead of git
This is do to the recent github change removing support for the unauthenticated git protocol on port 9418. For more info, see: https://github.blog/2021-09-01-improving-git-protocol-security-github/
If people depended on `git://` because of poor network connections, this may impact it (may want to switch to using `ssh://` in those cases).
Signed-off-by: Aaron Covrig <aarcov@gmail.com>