* feat: automatically use websockets if DERP upgrade is unavailable
This might be our biggest hangup for deployments at the moment...
Load balancers by default do not support the DERP protocol, so many
of our prospects and customers run into failing workspace connections.
This automatically swaps to use WebSockets, and reports the reason to
coderd.
In a future contribution, a warning will appear by the agent if it was
forced to use WebSockets instead of DERP.
* Fix nil pointer type in Tailscale dep
* Fix requested changes
Kyle Carberry