fix branding

Author: dawnerd

action.yml

@@ -1,8 +1,9 @@
 name: 'Swarmpit Stack Deploy'
 description: 'Deploys a stack from a passed docker compose file'
 author: 'First & Third'
-icon: arrow-up-circle
-color: purple
+branding:
+  icon: arrow-up-circle
+  color: purple
 inputs:
   url:
     required: true