ENH: macos-13 was deprecated, replace with macos-15-intel

The macos-15-intel is planned to be useful until
fall of 2027

Author: hjmjohnson

.github/workflows/ci.yml

@@ -20,7 +20,7 @@ jobs:
             arch: aarch64
           - os: ubuntu-22.04-arm
             arch: aarch64
-          - os: macos-13
+          - os: macos-15-intel
             arch: x86_64
           - os: macos-15
             arch: arm64