Pin msgpack library

Change-Id: Ia19b23c1e2b159028fdf9ed79714966226d6e316
diff --git a/Dockerfile b/Dockerfile
index 697aeef..e92f9cb 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,7 +1,7 @@
 FROM ubuntu:20.04
 
 LABEL maintainer="dev@mirantis.com"
-LABEL build_date="2021-07-01"
+LABEL build_date="2022-08-03"
 
 ENV DEBIAN_FRONTEND=noninteractive \
     DEBCONF_NONINTERACTIVE_SEEN=true \