Limit 'packaging' version

[VannTen]

This fixes the following error:

$ thoth-adviser 
Traceback (most recent call last):
  File "/home/max/.local/share/virtualenvs/adviser-ToNagSY3/bin/thoth-adviser", line 5, in <module>
    from thoth.adviser.cli import cli
  File "/home/max/.local/share/virtualenvs/adviser-ToNagSY3/lib/python3.8/site-packages/thoth/adviser/__init__.py", line 20, in <module>
    from .beam import Beam
  File "/home/max/.local/share/virtualenvs/adviser-ToNagSY3/lib/python3.8/site-packages/thoth/adviser/beam.py", line 34, in <module>
    from .state import State
  File "/home/max/.local/share/virtualenvs/adviser-ToNagSY3/lib/python3.8/site-packages/thoth/adviser/state.py", line 31, in <module>
    from thoth.python import PackageVersion
  File "/home/max/.local/share/virtualenvs/adviser-ToNagSY3/lib/python3.8/site-packages/thoth/python/__init__.py", line 20, in <module>
    from .aiosource import AIOSource
  File "/home/max/.local/share/virtualenvs/adviser-ToNagSY3/lib/python3.8/site-packages/thoth/python/aiosource.py", line 34, in <module>
    from .source import Source
  File "/home/max/.local/share/virtualenvs/adviser-ToNagSY3/lib/python3.8/site-packages/thoth/python/source.py", line 34, in <module>
    from packaging.version import LegacyVersion
ImportError: cannot import name 'LegacyVersion' from 'packaging.version' (/home/max/.local/share/virtualenvs/adviser-ToNagSY3/lib/python3.8/site-packages/packaging/version.py)

[harshad16]

/hold

[goern]

ping

[VannTen]

fixed by thoth-station/python#489
/close

[sesheta]

@VannTen: Closed this PR.

In response to this:

fixed by thoth-station/python#489
/close

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