Added pendingchanges

Signed-off-by: Nick Avramoussis <4256455+Idclip@users.noreply.github.com>

Author: Idclip

pendingchanges/cplusplus20.txt

@@ -0,0 +1,5 @@
+- Build:
+   - Improved support for compiling with C++20
+   [Contributed by Denys Maletskyy and Jérémie Dumas]
+   - OpenVDB's CMake no longer modifies the BUILD_SHARED_LIBS variable
+   [reported by Maksim Shabunin]