Update TransientStoreHandler.php

Update DummyTransientStoreHandler.php

Add ability to turn off state validation

Release 7.6.2 (auth0#478)

Release 7.6.2 (auth0#478)

Release 7.6.1 (auth0#472)

Release 7.6.0 (auth0#471)

Release 7.5.0 (auth0#464)

Release 7.4.0 (auth0#456)

Merge pull request auth0#452 from auth0/release-7.3.0

Release 7.3.0