fix(deps): loosen constraint for symfony/messenger

[Gounlaf]

Like Sylius/ShopApiPlugin#602: allow upgrade to symfony 4.4

[lchrusciel]

Hello Florian,

thanks for the contribution! Could you take a look into failing build?

[Gounlaf]

Hello Florian,

thanks for the contribution! Could you take a look into failing build?

Well, I can fix it if you want, but it's not related to this PR...

It's related to release 4.4.
IMO implemented method (execute) shouldn't have a return type (even if required php version is >= 7.2) to respect contract/parent method.
Another PR should be done to fix it;

[pamil]

There are BC breaks between Messenger 4.3 and 4.4, it might be worth to review them: https://github.com/symfony/symfony/blob/master/UPGRADE-4.4.md#messenger

[pamil]

Thanks, Florian! 🥇