mdolab/pyspline: v1.5.1

New features Add sol time by @joanibal in https://github.com/mdolab/pyspline/pull/40 ## Bug fixes flake8 fixes by @nwu63 in https://github.com/mdolab/pyspline/pull/32 ## Maintenance/documentation Added coverage reporting by @sseraj in https://github.com/mdolab/pyspline/pull/31 Update Curve Docs by @akleb in https://github.com/mdolab/pyspline/pull/33 Update azure-pipelines.yaml by @marcomangano in https://github.com/mdolab/pyspline/pull/36 Update make rules with proper format by @eirikurj in https://github.com/mdolab/pyspline/pull/37 update python deps by @joanibal in https://github.com/mdolab/pyspline/pull/39 Full Changelog: https://github.com/mdolab/pyspline/compare/v1.5.0...v1.5.