Update README.md

Author: simran2104

GUI_calculator/README.md

@@ -1,7 +1,8 @@
 <h1 align="center">Calculator</h1>
 <h4>A Calculator using Tk GUI toolkit Framework in Python.</h4>
 <br><br>
-<p align='center'>
-<img src="calculator.png"/></p>
+<p align="center">
+<img src="https://github.com/simran2104/Python-Projects/blob/main/GUI_calculator/demo.gif" >
+</p>
 <h3>Technology used:</h3>Python
 <h3>Library used:</h3>Tkinter