Fix quotes issue in readme.

Author: rossiam

README.md

@@ -1,13 +1,13 @@
 # SmartThings SmartApp NodeJS SDK (preview)
 
 <p align="center">
-<a href="https://www.npmjs.com/package/@smartthings/smartapp"><img src="https://badgen.net/npm/v/@smartthings/smartapp/></a>
-<a href="https://www.npmjs.com/package/@smartthings/smartapp"><img src="https://badgen.net/npm/license/@smartthings/smartapp/></a>
-<a href="https://status.badgen.net/"><img src="https://badgen.net/xo/status/@smartthings/smartapp/></a>
+<a href="https://www.npmjs.com/package/@smartthings/smartapp"><img src="https://badgen.net/npm/v/@smartthings/smartapp"/></a>
+<a href="https://www.npmjs.com/package/@smartthings/smartapp"><img src="https://badgen.net/npm/license/@smartthings/smartapp"/></a>
+<a href="https://status.badgen.net/"><img src="https://badgen.net/xo/status/@smartthings/smartapp"/></a>
 <a href="https://lgtm.com/projects/g/SmartThingsCommunity/smartapp-sdk-nodejs/context:javascript"><img alt="Language grade: JavaScript" src="https://img.shields.io/lgtm/grade/javascript/g/SmartThingsCommunity/smartapp-sdk-nodejs.svg?logo=lgtm&logoWidth=18"/></a>
 <a href="https://lgtm.com/projects/g/SmartThingsCommunity/smartapp-sdk-nodejs/alerts/"><img alt="Total alerts" src="https://img.shields.io/lgtm/alerts/g/SmartThingsCommunity/smartapp-sdk-nodejs.svg?logo=lgtm&logoWidth=18"/></a>
 <a href="https://snyk.io/test/github/SmartThingsCommunity/smartapp-sdk-nodejs?targetFile=package.json"><img src="https://snyk.io/test/github/SmartThingsCommunity/smartapp-sdk-nodejs/badge.svg?targetFile=package.json" alt="Known Vulnerabilities" data-canonical-src="https://snyk.io/test/github/SmartThingsCommunity/smartapp-sdk-nodejs?targetFile=package.json" style="max-width:100%;"></a>
-<a href="https://smartthingsdev.slack.com/messages/CG595N08N"><img src="https://badgen.net/badge//smartthingsdev?icon=slack/></a>
+<a href="https://smartthingsdev.slack.com/messages/CG595N08N"><img src="https://badgen.net/badge//smartthingsdev?icon=slack"/></a>
 </p>
 
 [Reference Documentation](doc/index.md)