Update the README to include UBI 9 (#62804)

Author: shahmishal

README.md

@@ -17,6 +17,7 @@
 | **CentOS 7** | x86_64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-centos-7/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-centos-7)|
 | **Amazon Linux 2** | x86_64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-amazon-linux-2/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-amazon-linux-2)|
 | **Amazon Linux 2** | AArch64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-amazon-linux-2-aarch64/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-amazon-linux-2-aarch64)|
+| **Universal Base Image 9** | x86_64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-ubi-9/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-ubi-9)|
 
 **Swift Community-Hosted CI Platforms**