There is no more need to set an accounting date as the usual date is now used.

add new files
fix pipeline requirements

 : Reviewed migration, play_onchanges usage, and unit tests

This would happen when running tests on a DB where ``account_period`` is
already installed.

Follow-up on rev 7bde6eae1dcf.

Upgraded the module version.
Updated the change log.

Specifics to play better with accounting changes:

* No longer change the base ``date`` field; add ``accounting_date`` instead.
* Build periods when loading accounting data for a new company.

 in tests, copy an existing product rather than creating a new one to avoid problems with new required fields in other modules
and also  remove description from manifest as README.rst will be used automatically instead

Updated the translations.
Updated the unit tests.

Same as Odoo 8 ones.

Updated the translations.
Executed "black" and "isort".