Related Issue or bug

• [Add Time Series specific metrics #1039]

Describe the changes you've made

Major changes of this branch include:

• Add SMAPE, MAPE, MASE, MAE and RMSE containers for time series. link

Minor changes include:

• Add sktime as a requirement to requirements-optional to ensure installation during CI stage. link

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, local variables)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Testing changes include:

• Added time series metrics testing to check_metric function. link
• Test float values through numpy.testing.assert_almost_equal. example

Checklist:

• My code follows the style guidelines of this project.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.
• Any dependent changes have been merged and published in downstream modules.