chore(dockerfile): remove unnecessary ubuntu docker base (#17)

Author: JonZeolla

cookiecutter.json

@@ -7,7 +7,6 @@
   "github_org": "zenable-io",
   "project_owner_github_username": "jonzeolla",
   "python_version": ["3.13", "3.12", "3.11"],
-  "docker_base": ["ubuntu:22.04", "ubuntu:20.04", "ubuntu:23.04"],
   "dockerhub": ["no", "yes"],
   "public": ["no", "yes"],
   "license": ["NONE", "MIT", "BSD-3-Clause"]