Update django-allauth to 0.30.0

[pyup-bot]

There's a new version of django-allauth available.
You are currently using 0.29.0. I have updated it to 0.30.0

These links might come in handy: PyPI | Changelog | Repo

Changelog

0.30.0

---

Note worthy changes

• Changed the algorithm that generates unique usernames. Previously, in case the
  provider did not hand over any information to base the username on, the
  username "user" extended with an ever increasing numeric suffix would be
  attempted until a free username was found. In case of a large number of
  existing users, this could result in many queries being executed before a free
  username would be found, potentially resulting in a denial of service. The new
  algorithm uses a random suffix and only one query to determine the final
  username.

• Added a new setting: ACCOUNT_PRESERVE_USERNAME_CASING. This setting
  determines whether the username is stored in lowercase (False) or whether
  its casing is to be preserved (True). Note that when casing is preserved,
  potentially expensive __iexact lookups are performed when filter on
  username. For now, the default is set to True to maintain backwards
  compatibility.

• The OAuth2Adapter class has gained a get_callback_url method for when
  customizing the callback URL is desired.

• The Battle.net login backend now accepts the region GET parameter.

• New providers: 500px, Discord.

Backwards incompatible changes

• In previous versions, the DefaultAccountAdapter contained a
  username_regex property and accompanying
  error_messages['invalid_username'] validation error message. These have
  been removed in favor of using the regex validation already defined at the
  user model level. Alternatively, you can use the newly introduced
  ACCOUNT_USERNAME_VALIDATORS setting.

• The Battle.net backend no longer overrides username regex validation. In
  order to use battletags as usernames, you are expected to override either
  the username field on your User model, or to pass a custom validator
  which will accept the ```` character using the new
  ACCOUNT_USERNAME_VALIDATORS setting. Such a validator is available in
  ``socialaccount.providers.battlenet.validators.BattletagUsernameValidator``.

Got merge conflicts? Close this PR and delete the branch. I'll create a new PR for you.

Happy merging! 🤖

[codecov-io]

Current coverage is 100% (diff: 100%)

Merging #147 into master will not change coverage

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