Features
* __breaking__ Drop support for Python 2 and Python 3.4
* __breaking__ Rename environment variable `TLDR_REMOTE_SOURCE` to `TLDR_SOURCE`
* __breaking__ Remove ability to print out multiple pages at the same time
* __breaking__ Make `--update` act the same as `--download_cache`, remove ability to only update currently cached pages
* __breaking__ Remove `--download_cache` flag (redundant to `--update`)
* __breaking__ Remove printing of tldr page to console width, and remove any ability to paint blank lines (see [98](https://github.com/tldr-pages/tldr-python-client/pull/98) for more info)
* Verify if colors specified via environment variables are valid, fallback to default if not
* Set `User-Agent` header for urlopen requests
* Allow specifying endpoints for pages and cache via environment variables
* Explicitly state support for Python 3.8
* Use default terminal colors instead of always white for printing text
* Catch KeyboardInterrupt exception to display appropriate message
* Add ability to disable SSL inspection
* Add `--version` flag to cli to print out cli version and supported client specification
* Move to using `long_description` and `long_description_content_type` to handle markdown README in setup.py
* Add support for handling pages in other languages
* Remove symlink script in-favor of entry_points again
* Narrow top-level catch-all exception to only catch urllib exceptions
Fixes
* Handle using `file://` as remote source for pulling pages
* Improve handling of environment variable colors to not be order specific of options
Chores
* Update LICENSE to LICENSE.md
* Move to GitHub actions from Travis-CI
* Use flake8 to lint codebase