doc: fix indent

readme.md

@@ -51,7 +51,7 @@ func main() {
 type CreateCustomerInput struct {
 	Name     string   `path:"name"`                 // you can extract value from: 'path', 'query', 'header', 'ctx'
 	Emails   []string `query:"emails" exploder:","` // exploder split value with the characters specified
-    Subject  string   `json:"body"`                 // it also works with json body
+	Subject  string   `json:"body"`                 // it also works with json body
 }
 
 // CustomerOutput is the output type of the http request.