Update CI runners to macOS 15

Author: finagolfin

.github/workflows/sdks.yml

@@ -11,10 +11,7 @@ jobs:
       fail-fast: false
       matrix:
         version: [release, devel, trunk]
-        os: [ubuntu-24.04, macos-13]
-        exclude:
-          - version: trunk
-            os: macos-13
+        os: [ubuntu-24.04, macos-15-intel]
     env:
       ANDROID_API_LEVEL: 24
       BUNDLE_VERSION: 0.1