Merge branch '527-update-t3o_membership-to-3-0-3-and-add-root-req-for-dbal-2-10-3' into 'develop'

Resolve "update t3o_membership to 3.0.3 and add root req for DBAL 2.10.3"

Closes #527

See merge request t3o/typo3.org!397