Update Dockerfile

Updates the Dockerfile to:
1. launch from within an Ubuntu instance so I can execute the .py scripts
2. install python3 and pip so that the requirements in requirements.txt can get installed

Dockerfile

@@ -1,8 +1,13 @@
-FROM python:3.11.9-slim-bullseye
+FROM ubuntu:22.04
 
 WORKDIR /usr/local/bin
 
 COPY requirements.txt .
+
+RUN apt-get update -y && apt-get upgrade -y && apt-get install -y \
+    python3 \
+    python3-pip
+
 RUN pip install -r requirements.txt
 
 COPY validate.py .