ci: Use macos-15-intel runners

Author: chrisburr

.github/workflows/build-and-test.yml

@@ -155,7 +155,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [macos-13]
+        os: [macos-15-intel]
     steps:
       - uses: actions/checkout@v3
       - name: Download installer