Disable MacOS until Apple Clang 14.0.3 is supported (for ranges::find_if)

It looks like `ranges::find_if` should be supported in Apple Clang 14.0.3, which is available since Xcode 14.3, released in March 2023 but apparently not yet installed on the VM/devbox we have access to here.

Author: hsutter

.github/workflows/build-cppfront.yaml

@@ -26,10 +26,10 @@ jobs:
             cxx-std: 'c++2b'
           - compiler: clang++-14
             cxx-std: 'c++2b'
-        include:
-          - runs-on: macos-latest
-            compiler: clang++
-            cxx-std: 'c++20'
+        # include:
+        #   - runs-on: macos-latest
+        #     compiler: clang++
+        #     cxx-std: 'c++20'
     runs-on: ${{ matrix.runs-on }}
     env:
       CXX: ${{ matrix.compiler }}