added branding and changed description

Added the branding list for icon and color and added a longer description explaining what we actually do.

Author: 6mile

action.yml

@@ -1,5 +1,8 @@
-name: 'SecureStack Exposure Analysis'
-description: 'Execute SecureStack Exposure Analysis'
+name: 'SecureStack Web Vulnerability Analysis'
+description: 'Scan your public deployment URL for security issues.  Works for dev, staging or prod.'
+branding:
+  icon: 'check'  
+  color: 'red'
 inputs:
   securestack_api_key:
     description: 'SecureStack API key - generate an API key at https://app.securestack.com'