build: disable apple-clang-15 builds until the crash is fixed

Author: mpusz

.github/generate-job-matrix.py

@@ -97,10 +97,11 @@ def make_msvc_config(release: str, version: int) -> Configuration:
         # arm64 runners are expensive; only consider one version
         if ver == 18 or platform != "arm64"
     ]
-    + [
-        make_apple_clang_config("macos-13", ver, std_format_support=False)
-        for ver in ["15.2"]
-    ]
+    # TODO uncomment the below when apple-clang-15 crash is fixed
+    # + [
+    #     make_apple_clang_config("macos-13", ver, std_format_support=False)
+    #     for ver in ["15.2"]
+    # ]
     # std::format is available in Xcode 16.1 or later
     + [
         make_apple_clang_config("macos-14", ver, std_format_support=True)