FIB: correctly report IPv6 FIB Unicast and Multicast memory usage (VPP-1578)"

and document scaling

Change-Id: I65d8999e65616d77e525963c770d91e9b0d5e593
Signed-off-by: Neale Ranns <nranns@cisco.com>
diff --git a/docs/about.rst b/docs/about.rst
index 277a2fb..65a66a9 100644
--- a/docs/about.rst
+++ b/docs/about.rst
@@ -4,6 +4,6 @@
 About
 =====
 
-**VPP Version:** 19.08-rc0~300-g9080096f7
+**VPP Version:** 19.08-rc0~307-g883a867
 
-**Built on:** Tue May 28 13:45:28 GMT 2019
+**Built on:** Wed May 29 06:27:33 GMT 2019