Update revision to 0.21.0

Signed-off-by: Eric Kunze <eric.kunze@arm.com>
Change-Id: Ie2d83c66600cb01f39992c6b0c168fea2917330c
diff --git a/Makefile b/Makefile
index 6718528..d1af64f 100644
--- a/Makefile
+++ b/Makefile
@@ -8,7 +8,7 @@
 # by a licensing agreement from ARM Limited.
 #
 
-TOSAREVISION=0.20.0
+TOSAREVISION=0.21.0
 MKDIR=mkdir -p
 ASCIIDOC=asciidoctor