Bump version to v1.11.0-rc5

Signed-off-by: Tibor Vass <tibor@docker.com>
diff --git a/VERSION b/VERSION
index 1cac385..629fe6d 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.11.0
+1.11.0-rc5