MacOS 12 -> 13 in Github action builds.

Author: tzlaine

.github/workflows/ci.yml

@@ -188,7 +188,7 @@ jobs:
           - name: "ASAN=on MAC_OSX=true Job 1"
             buildtype: "boost"
             packages: ""
-            os: "macos-12"
+            os: "macos-13"
             cxx: "clang++"
             sources: ""
             llvm_os: ""
@@ -199,7 +199,7 @@ jobs:
           - name: "ASAN=on MAC_OSX=true Job 2"
             buildtype: "boost"
             packages: ""
-            os: "macos-12"
+            os: "macos-13"
             cxx: "clang++"
             sources: ""
             llvm_os: ""