fix mqtt

xueyi-modules/xueyi-system/src/main/java/com/xueyi/system/digitalmans/controller/DmDigitalmanController.java

@@ -257,8 +257,8 @@ public class DmDigitalmanController extends BaseController<DmDigitalmanQuery, Dm
     }
 
 
-    @GetMapping("/api/mqtt/heartbeat/{message}")
-    public void heartbeat(@RequestParam(value = "message") String message) {
+    @PostMapping("/api/mqtt/heartbeat")
+    public void heartbeat(@RequestBody(required = true) String message) {
         JSONObject heartBeatObj = JSONObject.parseObject(message);
         String devId = heartBeatObj.getString("devId");
         String timestamp = heartBeatObj.getString("timestamp");