Remove trailing comma after the last property in manifest.json

The manifest.json file contains a trailing comma after the last property ("description"), which is not allowed in JSON.

Author: timbalabuch

public/manifest.json

@@ -38,5 +38,5 @@
       ]
     }
   ],
-  "description": "Ethereum is a global, decentralized platform for money and new kinds of applications. On Ethereum, you can write code that controls money, and build applications accessible anywhere in the world.",
-}
+  "description": "Ethereum is a global, decentralized platform for money and new kinds of applications. On Ethereum, you can write code that controls money, and build applications accessible anywhere in the world."
+}