Add entity namespace short aliases (Deprecated)

[ashishbhandariadesso]

doctrine/orm#8820

Updating doctrine orm from 2.14.0 to 2.14.3 results in the following error:

Context: Using short namespace alias "LeagueOAuth2ServerBundle" by calling
!! Doctrine\ORM\Configuration::addEntityNamespace
!! Problem: Feature was deprecated in doctrine/persistence 2.x and is not supp
!! orted by installed doctrine/persistence:3.x
!! Solution: See the doctrine/deprecations logs for new alternative approaches

[ashishbhandariadesso]

Closed issue as seems to be fixed in 0.5.0 version league/oauth2-server-bundle