Update README.md

Removed the dynamic lighthouse image from README.md because the app that it relied on is not working and the test that it was doing is no longer relevant since we simplified this app.

README.md

@@ -1,9 +1,7 @@
 Chrome Platform Status
 ==================
 
-[![Lighthouse score: 100/100](https://lighthouse-badge.appspot.com/?score=100&category=PWA)](https://github.com/ebidel/lighthouse-badge)
-
-[chromestatus.com](http://chromestatus.com/)
+[chromestatus.com](https://chromestatus.com/)
 
 ### Get the code