docs(release): changelog for v2.12 release

Change-Id: I5f4eb0ccff8dcd7e5cf3cd8c475057495e53c28f
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
diff --git a/Makefile b/Makefile
index e7efa2e..19f2a38 100644
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,7 @@
 
 # TFTF Version
 VERSION_MAJOR		:= 2
-VERSION_MINOR		:= 11
+VERSION_MINOR		:= 12
 
 MAKE_HELPERS_DIRECTORY := make_helpers/
 include ${MAKE_HELPERS_DIRECTORY}build_macros.mk