[playbook] Upgrade to SR to 1.0.56
The ERP5 software type changed to default, as create-erp5-site has been implemented there.
Upgrading to tag 1.0.56 requires to update the software_type of ERP5 to default, as it happened with recent changes in slapos.git repository for ERP5.
Cc: @rafael - please feel free to push it to proper audience.
The changes were merged into master.