Update django-anymail to 3.0

[pyup-bot]

This PR updates django-anymail from 1.4 to 3.0.

Changelog

3.0

Changes

* **Breaking change:** Python 3.3 is no longer supported (see 99).
* **Mailjet:** Fix tracking webhooks to work correctly when Mailjet "group events" option is disabled (see 106).
* **SendGrid:** Fix a problem where Anymail's status tracking webhooks didn't always receive the same `event.message_id` as the sent `message.anymail_status.message_id`, due to unpredictable behavior by SendGrid's API. Anymail now generates a UUID for each sent message and attaches it as a SendGrid custom arg named anymail_id. For most users, this change should be transparent. But it could be a **breaking change** if you are relying on a specific message_id format, or relying on message_id matching the *Message-ID* mail header or SendGrid's "smtp-id" event field. (More details in the [docs](https://anymail.readthedocs.io/en/stable/esps/sendgrid/sendgrid-message-id); also see 108.) Thanks to joshkersey for the report and the fix.
* Support Django 2.1 prerelease.

Deprecations

* This will be the last Anymail release to support Django 1.8, 1.9, and 1.10 (see 110).
* This will be the last Anymail release to support the legacy SendGrid v2 EmailBackend (see 111). (SendGrid's newer v3 API has been the default since Anymail v0.8.)
* Anymail v3.x will receive security updates and fixes for any breaking ESP API changes through at least April, 2019.
* If these deprecations affect you and you cannot upgrade, set your requirements to `django-anymail~=3.0` (a "compatible release" specifier, equivalent to `>=3.0,==3.*`).

2.2

Fix a breaking change accidentally introduced in v2.1: The boto3 package is no longer required if you aren't using Amazon SES.

2.1

**NOTE:** v2.1 accidentally introduced a **breaking change:** enabling Anymail webhooks with `include('anymail.urls')` causes an error if boto3 is not installed, even if you aren't using Amazon SES. This is fixed in v2.2.

New features

* **Amazon SES:** Newly-supported ESP ([docs](https://anymail.readthedocs.io/en/stable/esps/amazon_ses/)).
* **SparkPost:** Add SPARKPOST_API_URL setting to support SparkPost EU and SparkPost Enterprise ([docs](https://anymail.readthedocs.io/en/stable/esps/sparkpost/std:setting-ANYMAIL_SPARKPOST_API_URL)).

Other changes

* **Inbound:** Fix several issues with inbound messages, particularly around non-ASCII headers and body content. Add workarounds for some limitations in older Python email packages.
* **Postmark:** Update for Postmark "modular webhooks." This should not impact client code. (Also, older versions of Anymail will still work correctly with Postmark's webhook changes.)
* Use tox to manage Anymail test environments (see contributor [docs](https://anymail.readthedocs.io/en/stable/contributing/testing)).

Notice

This will be the last Anymail release to support Python 3.3. See 99 for more information.

2.0

Important updates
* **Breaking change:** Drop support for deprecated WEBHOOK_AUTHORIZATION setting. If you are using webhooks and still have this Anymail setting, you must rename it to WEBHOOK_SECRET. See the [v1.4 release notes](https://github.com/anymail/django-anymail/releases/tag/v1.4).

New features
* **SendinBlue:** Add new ESP ([docs](https://anymail.readthedocs.io/en/v2.0/esps/sendinblue/)). Thanks to RignonNoel for the implementation.
* Add EmailMessage `envelope_sender` attribute, which can adjust the message's Return-Path if supported by your ESP ([docs](https://anymail.readthedocs.io/en/v2.0/sending/anymail_additions/anymail.message.AnymailMessage.envelope_sender)).
* Add universal wheel to PyPI releases for faster installation.

Other changes
* Handle Reply-To, From, and To in EmailMessage `extra_headers` the same as Django's SMTP EmailBackend if supported by your ESP, otherwise raise an unsupported feature error. Fixes the SparkPost backend to be consistent with other backends if both `headers["Reply-To"]` and `reply_to` are set on the same message. If you are setting a message's `headers["From"]` or `headers["To"]` (neither is common), the new behavior is likely a **breaking change.** See [docs](https://anymail.readthedocs.io/en/v2.0/sending/django_email/additional-headers) and 91.
* Treat EmailMessage `extra_headers` keys as case-*insensitive* in all backends, for consistency with each other (and email specs). If you are specifying duplicate headers whose names differ only in case, this may be a **breaking change.** See [docs](https://anymail.readthedocs.io/en/v2.0/sending/django_email/additional-headers).
* Update setup.py metadata, clean up implementation. (Hadn't really been touched since original Djrill version.)
* Prep for Python 3.7.

Links

• PyPI: https://pypi.org/project/django-anymail
• Changelog: https://pyup.io/changelogs/django-anymail/
• Repo: https://github.com/anymail/django-anymail