Typing (#128)

* fix: CI yml name

* add: mypy configuraion

* add: type annotation to waybackpy modules

* add: type annotation to test modules

* fix: mypy command

* add: types-requests to dev deps

* fix: disable max-line-length

* fix: move pytest.ini into setup.cfg

* add: urllib3 to deps

* fix: Retry (ref: https://github.com/python/typeshed/issues/6893)

* fix: f-string

* fix: shorten long lines

* add: staticmethod decorator to no-self-use methods

* fix: str(headers)->headers_str

* fix: error message

* fix: revert "str(headers)->headers_str" and ignore assignment CaseInsensitiveDict with str

* fix: mypy error

requirements-dev.txt

@@ -3,7 +3,8 @@ click
 codecov
 flake8
 mypy
-setuptools>=46.4.0
 pytest
 pytest-cov
 requests
+setuptools>=46.4.0
+types-requests