Reduce jsonschema requirements to allow 3.2

The project I'm working on has a hard requirement of jsonschema 3.2 so currently, we have to use a horrible workaround to utilise st2, I'm hoping to remove this conflict.

test it

Try retriggerring by closing/reopening

The 3.6 tests are failing due to pep8 failing but that seems unrelated to my change -

  would reformat orquesta/tests/unit/conducting/test_workflow_conductor_data_flow.py
  would reformat orquesta/tests/unit/utils/test_strings.py
  
  Oh no! 💥 💔 💥
  2 files would be reformatted, 167 files would be left unchanged.
  Error: ERROR: InvocationError for command /home/runner/work/orquesta/orquesta/.tox/pep8/bin/black orquesta bin setup.py -l 100 --check (exited with code 1)

@guzzijones makes sense to revive this PR? I'm guessing the dependency update might be helpful here.