update macos runner to macos-13; macos-12 is no longer supported (#1940)

.github/workflows/artifacts.yml

@@ -33,10 +33,10 @@ jobs:
     strategy:
       matrix:
         include:
-          - os: macos-12
+          - os: macos-13
             kind: macOS
             target: osx-x64
-          - os: macos-12
+          - os: macos-13
             kind: macOS
             target: osx-arm64
     steps:

.github/workflows/pr.yml

@@ -54,7 +54,7 @@ jobs:
       - name: Test
         run: dotnet test --blame-hang-timeout "2m" --no-restore --verbosity normal
   build_and_test_mac:
-    runs-on: macos-12
+    runs-on: macos-13
     steps:
       - name: Get the sources
         uses: actions/checkout@v4