支持设置全局HTTPClient (#761)

* [新增]支持设置httpClient

* 增加说明

* 增加说明

* 格式化imports

* [fix]1.21.5 和golangci 有兼容性问题

* [fix]优化imports

wechat.go

@@ -1,6 +1,7 @@
 package wechat
 
 import (
+	"net/http"
 	"os"
 
 	log "github.com/sirupsen/logrus"
@@ -14,6 +15,7 @@ import (
 	openConfig "github.com/silenceper/wechat/v2/openplatform/config"
 	"github.com/silenceper/wechat/v2/pay"
 	payConfig "github.com/silenceper/wechat/v2/pay/config"
+	"github.com/silenceper/wechat/v2/util"
 	"github.com/silenceper/wechat/v2/work"
 	workConfig "github.com/silenceper/wechat/v2/work/config"
 )
@@ -81,3 +83,8 @@ func (wc *Wechat) GetWork(cfg *workConfig.Config) *work.Work {
 	}
 	return work.NewWork(cfg)
 }
+
+// SetHTTPClient  设置HTTPClient
+func (wc *Wechat) SetHTTPClient(client *http.Client) {
+	util.DefaultHTTPClient = client
+}