Update VERSION_WIN_SDK (#26797)
Update VERSION_WIN_SDK (#26797)

Make sure we get latest build tools/platform for Windows.  It wasn't previously failing, but now is.  Similar changes made to Linux/Mac recently.
cbracken/flutter,flutter/flutter,Hixie/flutter,tvolkert/flutter,flutter/flutter,tvolkert/flutter,cbracken/flutter,cbracken/flutter,Hixie/flutter,flutter/flutter,tvolkert/flutter,Hixie/flutter,flutter/flutter,tvolkert/flutter,flutter/flutter,flutter/flutter,cbracken/flutter,Hixie/flutter,cbracken/flutter,Hixie/flutter,cbracken/flutter,tvolkert/flutter,tvolkert/flutter,cbracken/flutter,Hixie/flutter,Hixie/flutter,tvolkert/flutter,tvolkert/flutter,flutter/flutter,cbracken/flutter,tvolkert/flutter,flutter/flutter,cbracken/flutter,flutter/flutter,Hixie/flutter,flutter/flutter,Hixie/flutter,Hixie/flutter,tvolkert/flutter,cbracken/flutter