* Switch mailgun webhooks to the webhook api
* Change mailgun strings to indicate application/json is in use
* Lint
* Revert Changes to .translations.
* Don't fail if the API key isn't set
* Switch mailgun to use webhook api
* Generalize webhook_config_entry_flow
* Add tests for webhook_config_entry_flow
* Add tests for mailgun
* Remove old mailgun file from .coveragerc
* Refactor WebhookFlowHandler into config_entry_flow
* Remove test of helper func from IFTTT
* Lint