CI: Make it possible to say macos-13

Author: olleolleolle

.github/workflows/ci.yaml

@@ -14,19 +14,19 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu]
+        os: [ubuntu-latest]
         ruby: ['2.5', '2.6', '2.7', '3.0', '3.1', '3.2']
         include:
           - os: macos-13
             ruby: '2.5'
-          - os: macos
+          - os: macos-latest
             ruby: '3.2'
-          - os: windows
+          - os: windows-latest
             ruby: '2.5'
-          - os: windows
+          - os: windows-latest
             ruby: '3.2'
 
-    runs-on: ${{ matrix.os }}-latest
+    runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
       - uses: ruby/setup-ruby@v1