update iotd 3rdlib build shell script for cjson

guowenxue

2021-05-02 aed475c7a57e329a3e90cce56d00ca997f519cda

 modules/python/sht20.py

old mode 100644
new mode 100755
@@ -1,4 +1,6 @@
#!/usr/bin/python
#-*- coding: utf-8 -*-

import fcntl
import time
import unittest