5.5 Travel Sample Python Update

Suggesting that the steps to run try-cb-python with Couchbase Server 5.0/5.5 should be on the master branch of the repository (currently on branch `5.0`). We could create a 4.6 branch for instructions that relate to running with Couchbase Server 4.6.

At the same time, we should also:

[ ] check that the app runs with Couchbase Server 5.5
[ ] update the tutorial content and screenshots to reference Couchbase Server 5.5

Using this ticket as reference before doing the same for other SDKs.