Update README.md

remove an unnecessary equal sign in the ENV description

Author: Yes-Sebastian

README.md

@@ -54,7 +54,7 @@ N8N_API_BASE_URL=https://your-n8n-instance.com/api/v1
 N8N_API_KEY=your_api_key
 
 N8N_WEBHOOK_BASE_URL=https://your-n8n-instance.com/webhook
-N8N_WEBHOOK_USERNAME==your_webhook_username
+N8N_WEBHOOK_USERNAME=your_webhook_username
 N8N_WEBHOOK_PASSWORD=your_webhook_password
 ```