Update readme with upcoming branch rename

README.md

@@ -1,14 +1,16 @@
 # News
 
-1. Visual Studio 2013 is no longer supported
+1. Default branch will be renamed from 'master' to 'main' [as requested by Khronos](https://github.com/KhronosGroup/glslang/issues/3107) on 01/30/2023.
+
+2. Visual Studio 2013 is no longer supported
 
    [As scheduled](https://github.com/KhronosGroup/glslang/blob/9eef54b2513ca6b40b47b07d24f453848b65c0df/README.md#planned-deprecationsremovals),
 Microsoft Visual Studio 2013 is no longer officially supported. \
    Please upgrade to at least Visual Studio 2015.
 
-2. The versioning scheme is being improved, and you might notice some differences.  This is currently WIP, but will be coming soon.  See, for example, PR #2277.
+3. The versioning scheme is being improved, and you might notice some differences.  This is currently WIP, but will be coming soon.  See, for example, PR #2277.
 
-3. If you get a new **compilation error due to a missing header**, it might be caused by this planned removal:
+4. If you get a new **compilation error due to a missing header**, it might be caused by this planned removal:
 
 **SPIRV Folder, 1-May, 2020.** Glslang, when installed through CMake,
 will install a `SPIRV` folder into `${CMAKE_INSTALL_INCLUDEDIR}`.