- Remove deprecated features and update deprecation notices for next
release.
- Update release notes.
- Bump version

- allow creation of offers of all types
- allow creation of vouchers with multiple offers
- allow creation of voucher sets of all usages, and with multiple offers

Where an initial value is required, this should be set on the form field
itself.

Fixes #3590.

Co-authored-by: Basil Dubyk <samitnuk.work@gmail.com>
Co-authored-by: Alexander Gaevsky <sasha@sasha0.ru>
Co-authored-by: Joseph Wayodi <jwayodi@gmail.com>

Fixes #3258.

Non-exclusive offers that only allow combination with specific other offers

These release notes were created in 6a03a0bc1f and 05b14af8af, but
somehow didn't make it into the master branch.

This is why http://docs.oscarcommerce.com/en/latest/releases/index.html
currently doesn't mention these releases.

Currently, if a valid basket line is marked for deletion, any other
invalid basket lines on the formset prevent it from being deleted.

Regression introduced in cca43aa4d1

Bumps [select2](https://github.com/select2/select2) from 4.0.8 to 4.0.10.
- [Release notes](https://github.com/select2/select2/releases)
- [Changelog](https://github.com/select2/select2/blob/develop/CHANGELOG.md)
- [Commits](https://github.com/select2/select2/compare/4.0.8...4.0.10)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [inputmask](https://github.com/RobinHerbots/Inputmask) from 4.0.2 to 4.0.8.
- [Release notes](https://github.com/RobinHerbots/Inputmask/releases)
- [Changelog](https://github.com/RobinHerbots/Inputmask/blob/5.x/CHANGELOG.md)
- [Commits](https://github.com/RobinHerbots/Inputmask/compare/4.0.2...4.0.8)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

So that migrations are not required for changes to the
"OSCAR_IMAGE_FOLDER" setting, for projects that have not forked the
"catalogue" app.

Bumps [select2](https://github.com/select2/select2) from 4.0.5 to 4.0.8.
- [Release notes](https://github.com/select2/select2/releases)
- [Changelog](https://github.com/select2/select2/blob/develop/CHANGELOG.md)
- [Commits](https://github.com/select2/select2/compare/4.0.5...4.0.8)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

``django-phonenumber-field`` supports the same versions of Python and Django that django-oscar supports, so this should be a safe upgrade.
Fixed failing test due to invalid phone number in fixtures.
References #3144

Also do some minor code cleanup for changes made in #3017.