[test.yml] Add macos-26 to the matrix.

Author: lgarron

.github/workflows/test.yml

@@ -5,7 +5,7 @@ jobs:
   test:
     strategy:
       matrix:
-        os: [macos-13, macos-14, macos-15]
+        os: [macos-13, macos-14, macos-15, macos-26]
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout code