Add Mac OS X 12 test target.

.github/workflows/c-cpp.yml

@@ -15,7 +15,7 @@ jobs:
       fail-fast: false
       matrix:
         # First we test all OSes in the default configuration.
-        os: [ubuntu-20.04, ubuntu-18.04, macos-10.15, macos-11.0]
+        os: [ubuntu-20.04, ubuntu-18.04, macos-10.15, macos-11, macos-12]
         configs: [default]
         # Then we include any extra configs we want to test for specific VMs.
         # Valgrind slows things down quite a bit, so start them first.
@@ -71,7 +71,8 @@ jobs:
           - { os: ubuntu-18.04, configs: kitchensink }
           - { os: ubuntu-18.04, configs: without-openssl }
           - { os: macos-10.15,  configs: pam }
-          - { os: macos-11.0,   configs: pam }
+          - { os: macos-11, configs: pam }
+          - { os: macos-12, configs: pam }
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v2