Merge pull request swiftlang#81276 from jamieQ/readme-universal-arch

[gardening]: update macos architecture wording in README build state matrix

Author: shahmishal

README.md

@@ -8,7 +8,7 @@
 
 | | **Architecture** | **Build** |
 |---|:---:|:---:|
-| **macOS**        | x86_64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-macos/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-macos)|
+| **macOS**        | Universal |[![Build Status](https://ci.swift.org/job/oss-swift-package-macos/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-macos)|
 | **Ubuntu 20.04** | x86_64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-ubuntu-20_04/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-ubuntu-20_04)|
 | **Ubuntu 20.04** | AArch64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-ubuntu-20_04-aarch64/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-ubuntu-20_04-aarch64)|
 | **Ubuntu 22.04** | x86_64 |[![Build Status](https://ci.swift.org/job/oss-swift-package-ubuntu-22_04/lastCompletedBuild/badge/icon)](https://ci.swift.org/job/oss-swift-package-ubuntu-22_04)|