Taking RMR v4.5.2 to use

Signed-off-by: wahidw <abdulwahid.w@nokia.com>
Change-Id: I16f700c346412e8cd045f652401f7c1db305e8bb
diff --git a/RELNOTES b/RELNOTES
index 0a980c6..aa347ea 100644
--- a/RELNOTES
+++ b/RELNOTES
@@ -1,3 +1,6 @@
+### v0.7.3
+* Upgraded to RMR v4.5.2
+
 ### v0.7.1
 * Upgraded to RMR v4.4.4