Update goimports

[jackwilsdon]

It appears that goimports and this repository have diverged again since #347, as they now disagree on this code;

import "github.com/dgrijalva/jwt-go"

golangci-lint wants this;

import jwt "github.com/dgrijalva/jwt-go"

Whereas goimports is fine with this;

import "github.com/dgrijalva/jwt-go"

It appears that a change was made to goimports which treats jwt-go and jwt as the same, by ignoring any characters after non-identifier runes (see golang/tools@cb89afa).

This PR simply updates golang.org/x/tools (and therefore goimports) such that the tools line up again at their latest versions.

[CLAassistant]

All committers have signed the CLA.

[jirfag]

hi, thank you!
because of conflicts I've updated it myself

[markus-wa]

@jirfag upgrading to 1.16.0 doesn't seem to fix this.

Installing golangci-lint: https://travis-ci.org/markus-wa/demoinfocs-golang/jobs/543361295#L527
Error: https://travis-ci.org/markus-wa/demoinfocs-golang/jobs/543361295#L555