ci: pin builds to macos-13

because libyaml 0.2.5 doesn't build cleanly on macos-14 yet for a variety of reasons

.github/workflows/packaged_tarball.yml

@@ -24,7 +24,7 @@ jobs:
       fail-fast: false
       matrix:
         ruby: ["3.0", "3.1", "3.2", "3.3", "head"]
-        runs-on: ["ubuntu-latest", "macos-latest", "windows-latest"]
+        runs-on: ["ubuntu-latest", "macos-13", "windows-latest"]
     runs-on: ${{matrix.runs-on}}
     steps:
       - uses: actions/checkout@v4