Dockerfile: apt-get update and apt-get upgrade to get latest OS packages

It upgrades the OS packages as well as pip itself.

Fixes: #59
Signed-off-by: Yaniv Kaul <yaniv.kaul@scylladb.com>

Dockerfile

@@ -8,6 +8,11 @@ RUN pip install --user .
 
 
 FROM python:3.11-slim-bullseye AS build-image
+
+# Upgrade packages to the latest, pip as well.
+RUN DEBIAN_FRONTEND=noninteractive apt-get update && apt-get upgrade && apt-get clean && rm -rf /var/lib/apt/lists/*
+RUN pip install --upgrade --no-cache-dir pip
+
 COPY --from=compile-image /root/.local /root/.local
 
 # Make sure scripts in .local are usable: