Implement Dependency.to_requirements_string#861

nathanjmcdougall merged 2 commits intomainusethis-python/usethis-python:mainfrom

850-a-method-on-the-dependency-object-to-display-it-as-a-requirements-stringusethis-python/usethis-python:850-a-method-on-the-dependency-object-to-display-it-as-a-requirements-stringCopy head branch name to clipboard