Update requirements so that clearml-agent is compatible with poetry

[idantene]

clearml-agent is incompatible with poetry with the latest pip versions (previous pip version did not crash on such mismatching requirements):

ERROR: Cannot install -r /tmp/cached-reqsroa73i6z.txt (line 14), -r /tmp/cached-reqsroa73i6z.txt (line 55) and jsonschema==3.2.0 because these package versions have conflicting dependencies.
The conflict is caused by:
    The user requested jsonschema==3.2.0
    clearml-agent 1.5.0 depends on jsonschema<3.3.0 and >=2.6.0
    poetry 1.2.2 depends on jsonschema<5.0.0 and >=4.10.0
To fix this you could try to:
1. loosen the range of package versions you've specified
2. remove package versions to allow pip attempt to solve the dependency conflict
ERROR: ResolutionImpossible: for help visit https://pip.pypa.io/en/latest/topics/dependency-resolution/#dealing-with-dependency-conflicts
clearml_agent: ERROR: Could not install task requirements!

[jkhenning]

@idantene please check v1.5.1rc0 🙂