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

engine/engine.go

@@ -708,8 +708,7 @@ func (bot *Engine) Stop() {
 
 	// Wait for services to gracefully shutdown
 	bot.ServicesWG.Wait()
-	err := gctlog.CloseLogger()
-	if err != nil {
+	if err := gctlog.CloseLogger(); err != nil {
 		log.Printf("Failed to close logger. Error: %v\n", err)
 	}
 }