🎨 Add branding to GitHub Action

📝 This commit enhances the visual appeal and recognition of our GitHub Action by adding branding elements:

- 🔀 Incorporates the 'git-pull-request' icon, perfectly representing the action's core functionality
- 🟢 Sets the color to 'green', giving a fresh and positive visual cue
- 🚀 Improves discoverability and professionalism of our action in the GitHub Marketplace

These branding additions will make our action stand out and provide users with a quick visual reference to its purpose.

action.yml

@@ -3,6 +3,9 @@
 name: 'Auto PR from dev to default'
 description: 'Creates or updates a PR from dev to the default branch, generates descriptions using OpenAI API, and adds reviewers.'
 author: 'Your Name'
+branding:
+  icon: 'git-pull-request'
+  color: 'green'
 inputs:
   openai_api_key:
     description: 'OpenAI API Key'