Fix some quality issues, add .deepsource.toml

Signed-off-by: Allen <allen@deepsource.io>

.deepsource.toml

@@ -0,0 +1,13 @@
+version = 1
+test_patterns = [
+  "*_test.go"
+]
+exclude_patterns = [
+  "examples/**",
+  "vendor/**"
+]
+[[analyzers]]
+name = "go"
+enabled = true
+  [analyzers.meta]
+  import_path = "github.com/messagebird/sachet"

cmd/sachet/main.go

@@ -218,7 +218,7 @@ func errorHandler(w http.ResponseWriter, status int, err error, provider string)
 	}
 	// respond json
 	bytes, _ := json.Marshal(data)
-	json := string(bytes[:])
+	json := string(bytes)
 	fmt.Fprint(w, json)
 
 	log.Println("Error: " + json)

provider/aliyun/aliyun.go

@@ -52,7 +52,7 @@ func (aliyun *Aliyun) Send(message sachet.Message) error {
 			var response *dysmsapi.SendSmsResponse
 			response, err = aliyun.client.SendSms(request)
 			if err == nil && (!response.IsSuccess() || response.Code != "OK") {
-				err = fmt.Errorf(response.String())
+				return fmt.Errorf(response.String())
 			}
 		}
 	default: