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/mock/recording.go

@@ -349,7 +349,10 @@ func CheckJSON(data interface{}, excluded *Exclusion) (interface{}, error) {
 				context[key] = 0.0 // Zero val float
 			}
 		case Slice:
-			slice := val.([]interface{})
+			slice, ok := val.([]interface{})
+			if !ok {
+				return nil, errors.New("unable to type assert slice")
+			}
 			if len(slice) < 1 {
 				// Empty slice found
 				context[key] = slice