chore: update runtime.es6.js template

Author: huturen

package.json

@@ -1,6 +1,6 @@
 {
   "name": "http-request-mock",
-  "version": "1.8.12",
+  "version": "1.8.13",
   "description": "Intercept & mock http requests issued by XMLHttpRequest, fetch, nodejs https/http module, axios, jquery, superagent, ky, node-fetch, request, got or any other request libraries by intercepting XMLHttpRequest, fetch and nodejs native requests in low level.",
   "main": "src/index.js",
   "module": "http-request-mock.esm.mjs",

tool/tpl/runtime.es6.js

@@ -1,6 +1,6 @@
 /* eslint-disable */
-let mocker;
 import HttpRequestMock from "__hrm_index_entry__";
+let mocker;
 
 /* __hrf_env_if__ */if (process.env.__hrm_environment_key__ === "__hrm_environment_val__") {
   mocker = HttpRequestMock.setup(__hrm_proxy_server__);