sktime v0.4.2

What's new Added ETSModel with auto-fitting capability (#393) @HYang1996 WEASEL classifier (#391) @patrickzib Full support for exogenous data in forecasting framework (#382) @mloning, (#380) @mloning Multivariate dataset for US consumption over time (#385) @SebasKoel Governance document (#324) @mloning, @fkiraly Fixed Documentation fixes (#400) @brettkoonce, (#399) @akanz1, (#404) @alwinw Changed Move documentation to ReadTheDocs with support for versioned documentation (#395) @mloning Refactored SFA implementation (additional features and speed improvements) (#389) @patrickzib Move prediction interval API to base classes in forecasting framework (#387) @big-o Documentation improvements (#364) @mloning Update CI and maintenance tools (#394) @mloning All contributors: @HYang1996, @SebasKoel, @fkiraly, @akanz1, @alwinw, @big-o, @brettkoonce, @mloning, @patrickzi