Synchronize version number with dask and distributed

I suggest to have the same version number as a compatible `dask` and `distributed` version.

It is extremely difficult to know which versions are compatible. It looks like just using the latest of all packages usually fails.

I ran into this now a second time. I could only resolve it by trial and error. Unfortunately the error messages are extremely unclear. Typically it is like this when creating a cluster: `GatewayClusterError: Cluster 'adrastea.b4286778ea9b49f4b4264f982f5b278d' failed to start, see logs for more information`

Similar behaviour has been reported in #348.

These logs are in a terminated pod and are hard to get, and don't tell much.

Another variant is that getting the client fails in an unclear way such as "no connection".

A related request suggesting better documentation of this is already given in #161.

But the best solution would be to synchronize the version numbers of all involved packages, another to show clear errors as it is today for Python version mismatches.

I think that the current behaviour is a showstopper for many less experienced users.