chore: 백엔드 배지 수정

Author: seo0o519

docs/index.html

@@ -1176,10 +1176,6 @@ <h3>🚀 Backend</h3>
           src="https://img.shields.io/badge/AWS_S3-569A31?style=for-the-badge&logo=amazons3&logoColor=white"
           alt="AWS S3"
         />
-        <img
-          src="https://img.shields.io/badge/Apache_Kafka-231F20?style=for-the-badge&logo=ApacheKafka&logoColor=white"
-          alt="Kafka"
-        />
         <img
           src="https://img.shields.io/badge/AWS_EC2-FF9900?style=for-the-badge&logo=amazonec2&logoColor=white"
           alt="AWS EC2"