Add instructions to use

[douglasdcm]

Hi, how are you? I was trying this project, but while running the file smell_detector.py with the old Python version 3.6 I had this error. Which Python version are you using? Doe this project depends on external libraries that I need to install? Could you add the instructions use it, please?

python smell_detector.py ../../guara/
Traceback (most recent call last):
  File "smell_detector.py", line 88, in <module>
    main()
  File "smell_detector.py", line 32, in main
    results_list = project_rule_runner(files)
  File "/home/douglas/repo/tmp-projects/PythonTestSmellDetector/test_smell_rule_runners.py", line 16, in project_rule_runner
    result = smell.test_for_smell(python_files)
  File "/home/douglas/repo/tmp-projects/PythonTestSmellDetector/test_smells/project_smells.py", line 24, in test_for_smell
    production_methods = discover_production_methods(file_list)
  File "/home/douglas/repo/tmp-projects/PythonTestSmellDetector/test_smells/project_smells.py", line 161, in discover_production_methods
    production_files = python_parser.filter_python_files_complement(file_list)
  File "/home/douglas/repo/tmp-projects/PythonTestSmellDetector/python_parser.py", line 83, in filter_python_files_complement
    tree = ast.parse(f.read())
  File "/usr/local/lib/python3.6/ast.py", line 35, in parse
    return compile(source, filename, mode, PyCF_ONLY_AST)
  File "<unknown>", line 1039
    def TypedDict(typename, fields=_marker, /, *, total=True, closed=False, **kwargs):
                                            ^
SyntaxError: invalid syntax

[douglasdcm]

Check PR #3