golangci-lint/CI: Bump versions and introduce new linters (#798)

* golangci-lint/CI: Bump versions

Fix remaining linter issues

* Specifically set AppVeyor version

* Fix the infamous typos 👀

* Add go env cmd to AppVeyor

* Add go version cmd to AppVeyor

* Specify AppVeyor image, adjust linters

* Update go get to go install due to deprecation

* Bump golangci-lint timeout time for AppVeyor

* Change NW contract to NQ

* Address nitters

* GetRandomPair -> Pair{}

* Address nits

* Address time nitterinos plus additional tweaks

* More time inception upgrades!

* Bending time and space

exchanges/stream/stream_match.go

@@ -48,8 +48,7 @@ func (m *Match) IncomingWithData(signature interface{}, data []byte) bool {
 func (m *Match) set(signature interface{}) (matcher, error) {
 	var ch chan []byte
 	m.Lock()
-	_, ok := m.m[signature]
-	if ok {
+	if _, ok := m.m[signature]; ok {
 		m.Unlock()
 		return matcher{}, errors.New("signature collision")
 	}