docs(readme): add Greenkeeper badge

greenkeeper[bot] · greenkeeper[bot] · commit 169c2ab7b0cf · 2018-09-19T08:22:26.000Z
diff --git a/README.md b/README.md
@@ -1,3 +1,5 @@
 # Fibonacci Example In WASM
 
+[![Greenkeeper badge](https://badges.greenkeeper.io/shekohex/fibonacci-wasm.svg)](https://greenkeeper.io/)
+
 Demo [Here](https://shekohex.github.io/fibonacci-wasm/)
