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

config/config.go

@@ -1870,7 +1870,7 @@ func (c *Config) AssetTypeEnabled(a asset.Item, exch string) (bool, error) {
 
 	err = cfg.CurrencyPairs.IsAssetEnabled(a)
 	if err != nil {
-		return false, nil
+		return false, nil // nolint:nilerr // non-fatal error
 	}
 	return true, nil
 }

config/config_encryption.go

@@ -34,8 +34,7 @@ func promptForConfigEncryption() (bool, error) {
 	log.Println("Would you like to encrypt your config file (y/n)?")
 
 	input := ""
-	_, err := fmt.Scanln(&input)
-	if err != nil {
+	if _, err := fmt.Scanln(&input); err != nil {
 		return false, err
 	}
 
@@ -194,8 +193,7 @@ func ConfirmECS(file []byte) bool {
 // or errors, if the prefix wasn't found
 func skipECS(file io.Reader) error {
 	buf := make([]byte, len(EncryptConfirmString))
-	_, err := io.ReadFull(file, buf)
-	if err != nil {
+	if _, err := io.ReadFull(file, buf); err != nil {
 		return err
 	}
 	if string(buf) != EncryptConfirmString {

config/config_encryption_test.go

@@ -130,8 +130,7 @@ func TestRemoveECS(t *testing.T) {
 func TestMakeNewSessionDK(t *testing.T) {
 	t.Parallel()
 
-	_, _, err := makeNewSessionDK(nil)
-	if err == nil {
+	if _, _, err := makeNewSessionDK(nil); err == nil {
 		t.Fatal("makeNewSessionDK passed with nil key")
 	}
 }
@@ -238,6 +237,7 @@ func TestSaveAndReopenEncryptedConfig(t *testing.T) {
 // setAnswersFile sets the given file as the current stdin
 // returns the close function to defer for reverting the stdin
 func setAnswersFile(t *testing.T, answerFile string) func() {
+	t.Helper()
 	oldIn := os.Stdin
 
 	inputFile, err := os.Open(answerFile)
@@ -359,6 +359,7 @@ func TestSaveConfigToFileWithErrorInPasswordPrompt(t *testing.T) {
 }
 
 func withInteractiveResponse(t *testing.T, response string, body func() error) error {
+	t.Helper()
 	// Answers to the prompt
 	responseFile, err := ioutil.TempFile("", "*.in")
 	if err != nil {

config/config_test.go

@@ -35,8 +35,7 @@ func TestGetNonExistentDefaultFilePathDoesNotCreateDefaultDir(t *testing.T) {
 	if file.Exists(dir) {
 		t.Skip("The default directory already exists before running the test")
 	}
-	_, _, err := GetFilePath("")
-	if err != nil {
+	if _, _, err := GetFilePath(""); err != nil {
 		t.Fatal(err)
 	}
 	if file.Exists(dir) {
@@ -921,7 +920,7 @@ func TestSupportsPair(t *testing.T) {
 			},
 		},
 	}
-	assetType := asset.Spot
+	assetType := asset.Spot // nolint // ifshort false positive
 	if cfg.SupportsPair("asdf",
 		currency.NewPair(currency.BTC, currency.USD), assetType) {
 		t.Error(
@@ -1284,7 +1283,7 @@ func TestGetForexProviders(t *testing.T) {
 
 func TestGetPrimaryForexProvider(t *testing.T) {
 	t.Parallel()
-	fxr := "Fixer"
+	fxr := "Fixer" // nolint:ifshort,nolintlint // false positive and triggers only on Windows
 	cfg := &Config{
 		Currency: CurrencyConfig{
 			ForexProviders: []currency.FXSettings{
@@ -1937,8 +1936,7 @@ func TestCheckConfig(t *testing.T) {
 			},
 		},
 	}
-	err := cfg.CheckConfig()
-	if err != nil {
+	if err := cfg.CheckConfig(); err != nil {
 		t.Fatal(err)
 	}
 }
@@ -2209,6 +2207,7 @@ func TestRemoveExchange(t *testing.T) {
 }
 
 func TestGetDataPath(t *testing.T) {
+	t.Parallel()
 	tests := []struct {
 		name string
 		dir  string
@@ -2238,6 +2237,7 @@ func TestGetDataPath(t *testing.T) {
 		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
+			t.Helper()
 			c := &Config{
 				DataDirectory: tt.dir,
 			}
@@ -2278,6 +2278,7 @@ func TestMigrateConfig(t *testing.T) {
 		{
 			name: "source present, no target dir",
 			setup: func(t *testing.T) {
+				t.Helper()
 				test, err := os.Create("test.json")
 				if err != nil {
 					t.Fatal(err)
@@ -2285,6 +2286,7 @@ func TestMigrateConfig(t *testing.T) {
 				test.Close()
 			},
 			cleanup: func(t *testing.T) {
+				t.Helper()
 				os.Remove("test.json")
 			},
 			args: args{
@@ -2297,6 +2299,7 @@ func TestMigrateConfig(t *testing.T) {
 		{
 			name: "source same as target",
 			setup: func(t *testing.T) {
+				t.Helper()
 				err := file.Write(filepath.Join(dir, File), nil)
 				if err != nil {
 					t.Fatal(err)
@@ -2312,6 +2315,7 @@ func TestMigrateConfig(t *testing.T) {
 		{
 			name: "source and target present",
 			setup: func(t *testing.T) {
+				t.Helper()
 				err := file.Write(filepath.Join(dir, File), nil)
 				if err != nil {
 					t.Fatal(err)