Stopped locking dependencies versions

[roll]

Thanks!

@akariv WDYT?

I think for Python our strategy is too aggressive. At least we need to drop the maximum version.

[akariv]

You're probably right @roll - The maximum version was originally there for things to be more predictable and not break when a dependency updates, bu usually what happens is that get a version mismatch with another library and things break anyway...

[organman91]

It looks like this breaks things with the recent release of jsonschema. Running pip install 'datapackage<2.0,>=1.2' gives the warning tableschema 1.4.0 has requirement jsonschema<3.0,>=2.5, but you'll have jsonschema 3.0.1 which is incompatible.

[KOLANICH]

Yet another argument against version locking. It is tableschema issue that it locks packages to old versions.