Update "upgrading" guide for Symfony5#12673

Merged

wouterj merged 3 commits intosymfony:4.4from

ThomasGallet:patch-1

Nov 23, 2019

Commits on Nov 22, 2019

[Messenger] Update version constraint for Redis extension
phansys
committed

Commits on Nov 23, 2019

minor #12659 [Messenger] Update version constraint for Redis extension (phansys)
wouterj
committed
Update "upgrading" guide for Symfony5

ThomasGallet
authored and
wouterj
committed