Bump version to v0.5.2

Signed-off-by: Jess Frazelle <acidburn@microsoft.com>
diff --git a/VERSION.txt b/VERSION.txt
index 992ac75..b0c2058 100644
--- a/VERSION.txt
+++ b/VERSION.txt
@@ -1 +1 @@
-v0.5.1
+v0.5.2