Update action.yml

Author: DKlinec

action.yml

@@ -1,4 +1,5 @@
 name: 'GPT Explain Diff'
+icon: message-square
 description: 'Asks OpenAI GPT to explain a git diff'
 inputs:
   diff:
@@ -12,4 +13,4 @@ outputs:
     description: 'The explanation received from GPT'
 runs:
   using: 'node16'
-  main: 'index.js'
+  main: 'index.js'