[BUILD] Build break on macOS 12

[marcalff]

The github macOS-latest label has changed from macOS-11 to macOS-12

actions/runner-images#6384

This exposes a new build break when compiling opentelemetry-cpp with all dependencies:

external/com_google_absl/absl/functional/function_ref.h:124:16: error: definition of implicit copy constructor for 'FunctionRef<void (absl::string_view)>' is deprecated because it has a user-declared copy assignment operator [-Werror,-Wdeprecated-copy]
  FunctionRef& operator=(const FunctionRef& rhs) = delete;
               ^
external/com_google_absl/absl/strings/cord.h:1325:33: note: in implicit copy constructor for 'absl::FunctionRef<void (absl::string_view)>' first required here
    return ForEachChunkAux(rep, callback);
                                ^
1 error generated.

Somehow this code is built with [-Werror,-Wdeprecated-copy], causing the warning to fail as an error.

Note that CLang was also changed from version 13.0 to 14.0.

[marcalff]

Caused by:

abseil/abseil-cpp#948

Fixed in Abseil by this commit:

abseil/abseil-cpp@702cae1