ci: drop macos-13 runner

Author: tklauser

.github/workflows/test.yml

@@ -14,7 +14,7 @@ jobs:
       matrix:
         # Latest two supported releases.
         go-version: ['1.24', '1.25']
-        os: [ubuntu-22.04, ubuntu-24.04, ubuntu-24.04-arm, macos-13, macos-14, macos-15, windows-2022, windows-2025]
+        os: [ubuntu-22.04, ubuntu-24.04, ubuntu-24.04-arm, macos-14, macos-15, windows-2022, windows-2025]
     runs-on: ${{ matrix.os }}
 
     steps: