Fixes sending "larger" email attachments using GOV.UK Notify
13.0.1
Includes minor updates to GOV.UK Notify support
13.0.0
Includes breaking change to email-sending functionality: Mailgun usage has been replaced with GOV.UK Notify
• `mtp_common.tasks.send_email` requires different parameters • GOV.UK Notify settings are required to be able to send emails • Mailgun / django-anymail settings no longer used