Support hyphenated filenames
* added support for hyphenated component filenames by wrabit in https://github.com/wrabit/django-cotton/pull/214
This introduces a new config option as detailed in the docs: https://django-cotton.com/docs/configuration.
Summary
`<c-my-button />`
Filepath before: `cotton/my_button.html`
Filepath after: `cotton/my-button.html`
(with `COTTON_SNAKE_CASED_NAMES = False`)
What else
* raise value error when multiple c-vars provided by wrabit in https://github.com/wrabit/django-cotton/pull/213
Cotton only supports a maximum of 1 `c-vars` tag per component. Some user's reach for using multiple, which is not currently supported. To ensure this is clear, cotton now raises an exception when it detects more than one `c-vars` in a component.
**Full Changelog**: https://github.com/wrabit/django-cotton/compare/v1.2.1...v1.3.0