add graphql conf 2024 banner (#10080)

Author: saihaj

README.md

@@ -1,7 +1,9 @@
+[![GraphQLConf 2024 Banner: September 10-12, San Francisco. Hosted by the GraphQL Foundation](https://github.com/user-attachments/assets/bdb8cd5d-5186-4ece-b06b-b00a499b7868)](https://graphql.org/conf/2024/?utm_source=github&utm_medium=graphql_codegen&utm_campaign=readme)
+
 <div>
     <img src="./logo.svg" width="150px" alt="GraphQL Code Generator logo"/>
     <a href="https://the-guild.dev">
-        <img align="right" src="https://the-guild-org.github.io/press-kit/full-dark-logo.svg" alt="Created by The Guild" style="width: 100px;align:right;"/> 
+        <img align="right" src="https://the-guild-org.github.io/press-kit/full-dark-logo.svg" alt="Created by The Guild" style="width: 100px;align:right;"/>
     </a>
 </div>