Update crow to improve security

Change-Id: I86146edde21bac89e6cc30afdd79690e2b0adadd
diff --git a/include/webassets.hpp b/include/webassets.hpp
index 3afa61f..6fd0d60 100644
--- a/include/webassets.hpp
+++ b/include/webassets.hpp
@@ -87,7 +87,7 @@
           }
         }
       }
-      app.route_dynamic(std::string(webpath.string()))(
+      app.route_dynamic(webpath.string())(
           [is_gzip, absolute_path_str, content_type](const crow::request& req,
                                                      crow::response& res) {
             static const char* content_type_string = "Content-Type";