Fix Dockerfiles to add missing apt-update before apt-install

Change-Id: I639aed00e74c64e770566ce50de10e193e8b8d01
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/docker/POL/Dockerfile b/docker/POL/Dockerfile
index d9585d5..6a731fd 100644
--- a/docker/POL/Dockerfile
+++ b/docker/POL/Dockerfile
@@ -31,7 +31,8 @@
     python3-setuptools=45.2.* \
     curl=7.68.*
 
-RUN DEBIAN_FRONTEND=noninteractive apt-get --yes install \
+RUN DEBIAN_FRONTEND=noninteractive apt-get --yes update && \
+    DEBIAN_FRONTEND=noninteractive apt-get --yes install \
     mysql-client-core-8.0=8.0.*
 
 ARG PYTHON3_OSM_COMMON_URL