fix: remove macOS 15 from CI build matrix. It was already being tested by

the test-macos-homebrew job, and it conflicts with the actual build
that we want, which is macOS 14 for backwards-compatibility.

Signed-off-by: deadprogram <ron@hybridgroup.com>

.github/workflows/build-macos.yml

@@ -18,14 +18,12 @@ jobs:
       matrix:
         # macos-13: amd64 (oldest supported version as of 18-10-2024)
         # macos-14: arm64 (oldest arm64 version)
-        os: [macos-13, macos-14, macos-15]
+        os: [macos-13, macos-14]
         include:
           - os: macos-13
             goarch: amd64
           - os: macos-14
             goarch: arm64
-          - os: macos-15
-            goarch: arm64
     runs-on: ${{ matrix.os }}
     steps:
       - name: Install Dependencies