Update MacOS Github runners in ci to MacOS 15

Author: mcbarton

.github/workflows/main.yml

@@ -40,16 +40,16 @@ jobs:
                 -DLLVM_HOST_TRIPLE=aarch64-linux-gnu
                 -DRUST_TARGET=aarch64-unknown-linux-gnu
 
-          - artifact: arm64-macos
-            os: macos-14
+          - artifact: arm64-macos-15
+            os: macos-15
             rust_target: aarch64-apple-darwin
             env:
               WASI_SDK_CI_TOOLCHAIN_LLVM_CMAKE_ARGS: >-
                 -DCMAKE_OSX_DEPLOYMENT_TARGET=10.12
                 -DCMAKE_OSX_ARCHITECTURES=arm64
-
-          - artifact: x86_64-macos
-            os: macos-14
+          
+          - artifact: x86_64-macos-15
+            os: macos-15
             rust_target: x86_64-apple-darwin
             env:
               WASI_SDK_CI_SKIP_SYSROOT: 1