feat: adding logic to enable use with earlier supported python versions

[mini-moose]

Resolves #71

Summary

• Import __future__.annotations to allow type hinting across all supported versions
• Added sys.version_info check to ensure Python version being used is supported by the tool.
• Added sys.version_info check to import tomllib only if Python version is compatible. Otherwise imports tomli as tomllib to ensure functionality in earlier supported Python versions.
• Added line to .gitignore to ignore versioned .venv directories.

Changes

File	Purpose
/src/config.py	Import future.annotations, tomllib => tomli downgrade logic to enable earlier supported versions
.gitignore	Ignore versioned .venv files (ex. .venv-3.8, .venv-3.11.7)