Merge pull request #1431 from josh/macos-26

Update macOS version in CI workflow

Author: josh

.github/workflows/nix.yml

@@ -15,7 +15,7 @@ jobs:
         os:
           - "ubuntu-24.04"
           - "ubuntu-24.04-arm"
-          - "macos-15"
+          - "macos-26"
 
     runs-on: ${{ matrix.os }}