adds version option

[LucaSforza]

As requested in #66 I created the option to print the version on dbtc

[dpguthrie]

Thanks for opening this up @LucaSforza, I appreciate the contribution! Couple of comments:

• I think __version__ should exist in its own file - _version.py
• I'd like to investigate using this approach here to try and have a single place where version needs to be updated with poetry version <version>

[LucaSforza]

I added the function version(__package__) imported from module importlib_metadata,so I no longer use any global variables.

Now I should have solved the problem, tell me if everything is OK

[dpguthrie]

Thanks for making some of those changes. Couple things that I'd like to see though:

• I think the __version__ variable should be in its own _verison.py file next to __init__.py.
• This variable should be imported into __init__.py also so it's available to the python package as well.

Also, it looks like your last commit included some irrelevant files .DSStore.

[LucaSforza]

Ok i created the file _version.py with inside has the variable __version__ ,please update me if everything is fine this time

[dpguthrie]

Could you remove the .DSStore file in this PR?

[LucaSforza]

Ok, sorry I didn't see that there were others left, now they should all have been deleted