PIM-3282: fix the grid filters that can be set as json in the request
Preparing version 1.2.9

Conflicts:
	CHANGELOG.md
	src/Pim/Bundle/CatalogBundle/Version.php
PIM-3221: Fix bug on variant group import

*Fix bug on variant group import, possibility to update variant
groups's attributes on import and it shouldn't be possible (currently it display a
error message)

*Improved the behats

Conflicts:
	CHANGELOG.md
	src/Pim/Bundle/CatalogBundle/Validator/Constraints/ImmutableValidator.php
PIM-3283: Password reset does not work

Conflicts:
	src/Pim/Bundle/UserBundle/DependencyInjection/PimUserExtension.php
PIM-1154: Changed grid no results message on search
PIM-3250 : update upgrade doc
PIM-3250 : check locale and scope in completeness sorter
PIM-3250 : use AttributeInterface to replace AbstractAttribute
PIM-3250 : check the locale in family sorter and add related spec
PIM-3250 : add type hinting