Updated version and release notes

Author: John Wellbelove

support/Release notes.txt

@@ -2,6 +2,7 @@
 20.43.1
 
 Updates:
+Added automatic use of __builtin_memcpy, __builtin_memmove, __builtin_memset, __builtin_memcmp, and __builtin_memchr for GCC and Clang, if available.
 #1170 Place a typed pointer instead of a bool into etl::typed_storage
       Modified the storage used by etl::typed_storage to be a union, along the lines of etl::optional.
       Added etl::typed_storage_ext to wrap external storage.