Feature Request: Readme change to explain when to use vanguard-go vs connect-go

[evanmoran]

Hi there! I think this vanguard-go README (and maybe website docs) should have a section at the top explaining when vanguard-go vs connect-go is needed. I spent a little too long trying to figure this out and know that I understand better what vanguard-go is for I suspect most new users of connectrpc would be better off using connect-go by default. Thank you for all your great work, connect is really powerful so far.

Thanks! -Evan