Compile and run using Go 1.17.7

[jmwample]

Getting the repo up and running using 1.17.7 took some small fixes:

• modularize repo - declaring repo as the github.com/lucas-clemente/quic-go module allows it to reference internal dependencies properly in newer versions of go
• fix format strings - there were hanging formatting directives in client.go and server.go that the compiler was upset about. I assume, given context of surrounding lines, that they meant to reference the ConnectionID in the infof errors printed.
• pin bifurcation/mint to a6080d (in go.mod)

[qdeconinck]

I assume only #33 should be considered and not this one.