Warnings when running the test suite

[niconoe]

• pywhip version: 0.3.3
• Python version: 3.7 (via Anaconda)
• Operating System: Mac OS

Description

Got a ton (147) of warnings when running the test suite. Fortunately, most of them are identical:

tests/test_validators.py::TestRequiredValidator::test_required_term
  /Users/nicolas_noe/pywhip/tests/test_validators.py:1530: YAMLLoadWarning: calling yaml.load() without Loader=... is deprecated, as the default Loader is unsafe. Please read https://msg.pyyaml.org/load for full details.
    schema = yaml.load(self.yaml_multiple_term)

What I Did

$ python setup.py test

[niconoe]

Update: fixed the warnings related to YAML loading.

Next steps: also fix the "invalid escape sequence" warnings. Some are due to regexp that don't use raw strings, but others are more difficult to debut since pytest doesn't give location:

<unknown>:1
<unknown>:1
<unknown>:1
<unknown>:1
<unknown>:1
<unknown>:1
<unknown>:1
<unknown>:1
  <unknown>:1: DeprecationWarning: invalid escape sequence \?

Another next step: check if examples and documentation should also be updated to avoid YAML warnings (basically, add a parameter to each yaml.load() call: Loader=yaml.FullLoader)