Update README.md - Fix rocky 9 badge (#12423)

Rocky 9 badge is pointing to rocky 8

Author: ezelkow1

README.md

@@ -9,7 +9,7 @@
 [![Jenkins](https://img.shields.io/jenkins/build?jobUrl=https%3A%2F%2Fci.trafficserver.apache.org%2Fjob%2Fmaster%2Fjob%2Fosx%2F&label=macOS)](https://ci.trafficserver.apache.org/job/master/job/osx/)
 [![Jenkins](https://img.shields.io/jenkins/build?jobUrl=https%3A%2F%2Fci.trafficserver.apache.org%2Fjob%2Fmaster%2Fjob%2Fosx-m1%2F&label=macOS%20arm64)](https://ci.trafficserver.apache.org/job/master/job/osx-m1/)
 [![Jenkins](https://img.shields.io/jenkins/build?jobUrl=https%3A%2F%2Fci.trafficserver.apache.org%2Fjob%2Fmaster%2Fjob%2Fos-rockylinux_8%2F&label=Rocky%20Linux%208)](https://ci.trafficserver.apache.org/job/master/job/os-rockylinux_8/)
-[![Jenkins](https://img.shields.io/jenkins/build?jobUrl=https%3A%2F%2Fci.trafficserver.apache.org%2Fjob%2Fmaster%2Fjob%2Fos-rockylinux_8%2F&label=Rocky%20Linux%209)](https://ci.trafficserver.apache.org/job/master/job/os-rockylinux_9/)
+[![Jenkins](https://img.shields.io/jenkins/build?jobUrl=https%3A%2F%2Fci.trafficserver.apache.org%2Fjob%2Fmaster%2Fjob%2Fos-rockylinux_9%2F&label=Rocky%20Linux%209)](https://ci.trafficserver.apache.org/job/master/job/os-rockylinux_9/)
 [![Jenkins](https://img.shields.io/jenkins/build?jobUrl=https%3A%2F%2Fci.trafficserver.apache.org%2Fjob%2Fmaster%2Fjob%2Fos-ubuntu_20.04%2F&label=Ubuntu%2020.04)](https://ci.trafficserver.apache.org/job/master/job/os-ubuntu_20.04/)
 [![Jenkins](https://img.shields.io/jenkins/build?jobUrl=https%3A%2F%2Fci.trafficserver.apache.org%2Fjob%2Fmaster%2Fjob%2Fos-ubuntu_22.04%2F&label=Ubuntu%2022.04)](https://ci.trafficserver.apache.org/job/master/job/os-ubuntu_22.04/)
 [![Jenkins](https://img.shields.io/jenkins/build?jobUrl=https%3A%2F%2Fci.trafficserver.apache.org%2Fjob%2Fmaster%2Fjob%2Fos-ubuntu_23.04%2F&label=Ubuntu%2023.04)](https://ci.trafficserver.apache.org/job/master/job/os-ubuntu_23.04/)