Tests fail with ruamel.yaml 0.18.0

[Lily Foster]

Environment

• Python version: 3.11.
• PyKwalify version: 1.8.0

Steps to Reproduce

1. git clone https://github.com/Grokzen/pykwalify.git && cd pykwalify
2. pip install -r dev-requirements.txt
3. pytest

Expected Behavior

Tests to run successfully

Observed Behavior

Errors like the following are observed in a handful of tests:

E           AttributeError:
E           "safe_load_all()" has been removed, use
E
E             yaml = YAML(typ='safe', pure=True)
E             yaml.load_all(...)
E
E           instead of file "/home/lily/src/pykwalify/tests/test_core.py", line 582
E
E                           yaml_data = yaml.safe_load_all(stream)

E           AttributeError:
E           "safe_dump()" has been removed, use
E
E             yaml = YAML(typ='safe', pure=True)
E             yaml.dump(...)
E
E           instead of file "/home/lily/src/pykwalify/tests/test_unicode.py", line 50
E
E                   source_f.write(yaml.safe_dump(fail_data_2s_yaml, allow_unicode=True))