Specified Docker base image version

Previously, generic latest version of official Ubuntu docker image was being used.

Can use latest versioned image, whichever is the latest available one with low vulnerabilities and packages upgraded to required versions.

Ubuntu docker images found here:
https://hub.docker.com/_/ubuntu/tags

Dockerfile

@@ -1,5 +1,5 @@
 # python 3
-FROM ubuntu:jammy
+FROM ubuntu:jammy-20231004
 
 MAINTAINER K. Shankari ([email protected])
 
@@ -16,8 +16,6 @@ RUN apt-get install -y -qq wget
 # install jq to parse json within bash scripts
 RUN apt-get install -y jq
 
-RUN apt-get -y -qq update && apt-get -y -qq upgrade
-
 # cleanup
 RUN apt-get -y remove --purge build-essential
 RUN apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*