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

gctscript/wrappers/gct/exchange/exchange_test.go

@@ -47,8 +47,7 @@ var (
 
 func TestMain(m *testing.M) {
 	var t int
-	err := setupEngine()
-	if err != nil {
+	if err := setupEngine(); err != nil {
 		fmt.Printf("Failed to configure exchange test cannot continue: %v", err)
 		os.Exit(1)
 	}
@@ -59,10 +58,8 @@ func TestMain(m *testing.M) {
 
 func TestExchange_Exchanges(t *testing.T) {
 	t.Parallel()
-	x := exchangeTest.Exchanges(false)
-	y := len(x)
-	if y != 1 {
-		t.Fatalf("expected 1 received %v", y)
+	if x := exchangeTest.Exchanges(false); len(x) != 1 {
+		t.Fatalf("expected 1 received %v", x)
 	}
 }