Add updating flexsea version to Dephy troubleshooting

I installed the latest version of the osl library but got an error in flexsea/device.py because the flexsea version wasn't the most updated. 

It would be helpful if there was a note in the tutorials Getting Started document for checking the flexsea version when working with the Dephy actuator. It only mentions flexsea as a dependency under the Installation guide. 
