change extrypoint to cmd

[steevehook]

trafficstars

This PR leaves everything exactly the same except it allows for command override

[wallyqs]

I think this might be fine to include but need to double check that it may not break other areas like the Helm charts, there is also docker run --entrypoint that might help in the mean time.

[steevehook]

It won't break anything it will acts as ENTRYPOINT except people now can overwrite the command without specifying entrypoint. This is especially useful when execing on already running containers

[caleblloyd]

Fixed in #47 and will be in next release