Update README.md

Author: stephenberry

README.md

@@ -180,7 +180,7 @@ auto ec = glz::write_file_json(obj, "./obj.json", std::string{});
 
 ![clang build](https://github.com/stephenberry/glaze/actions/workflows/clang.yml/badge.svg) ![gcc build](https://github.com/stephenberry/glaze/actions/workflows/gcc.yml/badge.svg) ![msvc build](https://github.com/stephenberry/glaze/actions/workflows/msvc.yml/badge.svg) 
 
-> Glaze seeks to maintain compatibility with the latest three versions of GCC and Clang, as well as the latest version of MSVC and Apple Clang.
+> Glaze seeks to maintain compatibility with the latest three versions of GCC and Clang, as well as the latest version of MSVC and Apple Clang (Xcode). And, we aim to only drop old versions with major releases.
 
 ### MSVC Compiler Flags