trivrost version in http client string

[dragetd]

Is your feature request related to a problem? Please describe.
Looking into the HTTP logs, it would be nice to see from which version the request is coming.

Describe the solution you'd like
Currently it says 'Go-http-client/1.1' - could be 'Go-http-client/1.1-trivrost/1.5.0' or something like this (not sure if there are specs for this)

Describe alternatives you've considered
none