Allow some symfony/* dependencies to use version ^5.1

[phansys]

Subject

Allow some symfony/* dependencies to use version ^5.1, since these major versions don't have breaking changes. See:

• https://github.com/symfony/options-resolver/blob/v5.0.0/CHANGELOG.md#500;
• https://github.com/symfony/property-access/blob/v5.0.0/CHANGELOG.md.

I am targeting this branch, because these changes respect BC.

Depends on sonata-project/SonataAdminBundle#6299, sonata-project/SonataMediaBundle#1786.

Changelog

### Added
- Added support for symfony/options-resolver:^5.1;
- Added support for symfony/property-access:^5.1.

[franmomu]

Thanks @phansys!