Update dependency macos to v15 (#1707)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/build.yml

@@ -124,7 +124,7 @@ jobs:
           path: '**/build/reports'
 
   publish:
-    runs-on: macos-14
+    runs-on: macos-15
     if: github.repository == 'square/okio' && github.ref == 'refs/heads/master'
     needs: [jvm, all-platforms, emulator]
 

.github/workflows/release.yaml

@@ -10,7 +10,7 @@ env:
 
 jobs:
   publish:
-    runs-on: macos-14
+    runs-on: macos-15
 
     steps:
       - uses: actions/checkout@v5