.github/workflows/build_wheels.yml: Replace macos-13 runner by macos-15-intel

Author: mkoeppe

.github/workflows/build_wheels.yml

@@ -30,7 +30,7 @@ jobs:
             arch: x86_64
           - os: macos-14
             arch: arm64
-          - os: macos-13
+          - os: macos-15-intel
             arch: x86_64
           - os: windows-latest
             arch: AMD64