Restore PHPCR for Symfony 6

[alexislefebvre]

Is your feature request related to a problem? Please describe.
Since #160, PHPCR is disabled when testing the bundle with Symfony 6 :

LiipTestFixturesBundle/.github/workflows/tests.yml

Lines 86 to 88 in 87e1f44

	- name: Remove PHPCR with Symfony 6
	if: matrix.symfony-version == '^6.0'
	run: composer remove --no-update --dev doctrine/phpcr-bundle doctrine/phpcr-odm

Describe the solution you'd like
Restore PHPCR for Symfony 6.

Describe alternatives you've considered
.

Additional context
It will require doctrine/phpcr-odm#821 and an update in https://github.com/doctrine/DoctrinePHPCRBundle/blob/master/composer.json