version update

[klimenttoshkov]

requirements need updating to be installed with latest symfony/event-dispatcher

  Problem 1
    - Root composer.json requires piece/stagehand-fsm ^2.6 -> satisfiable by piece/stagehand-fsm[v2.6.0, 2.6.x-dev].
    - piece/stagehand-fsm[v2.6.0, ..., 2.6.x-dev] require symfony/event-dispatcher ~2.8|~3.0|~4.0 -> found symfony/event-dispatcher[v2.8.0-BETA1, ..., 2.8.x-dev, v3.0.0-BETA1, ..., 3.4.x-dev, v4.0.0-BETA1, ..., 4.4.x-dev] but the package is fixed to v6.1.0 (lock file version) by a partial update and that version does not match. Make sure you list it as an argument for the update command.