ci: Update CD workflow to explicitly use "macos-15-intel" for macOS x86_64

Author: jcfr

.github/workflows/cd.yml

@@ -81,7 +81,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, windows-latest, macos-latest]
+        os: [ubuntu-latest, windows-latest, macos-15-intel]
         arch: ["auto"]
 
         include: