Log Message:
py-dotenv: updated to 0.21.0

0.21.0

Added
* CLI: add support for invocations via 'python -m'.
* `load_dotenv` function now returns `False`.
* CLI: add --format= option to list command.

Fixed
* Drop Python 3.5 and 3.6 and upgrade GA
* Use `open` instead of `io.open`.
* Improve documentation for variables without a value
* Add `parse_it` to Related Projects by
* Update README.md by
* Improve documentation with direct use of MkDocs by