Bump golangci-lint to v1.24.0, linter fixes and general code improvements (#478)

* Bump golangci-lint version, update Go version deps and generic code improvements

* Fix wesbocket resp nil check and zip closures

* Update pprof path

exchanges/websocket/wsorderbook/wsorderbook.go

@@ -259,8 +259,9 @@ func (w *WebsocketOrderbookLocal) LoadSnapshot(newOrderbook *orderbook.Base) err
 // calculation and cause problems
 func (w *WebsocketOrderbookLocal) GetOrderbook(p currency.Pair, a asset.Item) *orderbook.Base {
 	w.m.Lock()
-	defer w.m.Unlock()
-	return w.ob[p][a]
+	ob := w.ob[p][a]
+	w.m.Unlock()
+	return ob
 }
 
 // FlushCache flushes w.ob data to be garbage collected and refreshed when a