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/asset/asset_test.go

@@ -62,8 +62,7 @@ func TestIsValid(t *testing.T) {
 }
 
 func TestNew(t *testing.T) {
-	_, err := New("Spota")
-	if err == nil {
+	if _, err := New("Spota"); err == nil {
 		t.Fatal("TestNew returned an unexpected result")
 	}