danforthcenter/plantcv: PlantCV v3.0

With PlantCV v3.0 PlantCV should be available on PyPI (if all goes well). Big thanks to @HaleySchuhl and @dschneiderch for all the pull requests and all the other contributors. PlantCV v3.0 contains the following new features/changes: plantcv.fill is now significantly faster using a scikit-image backend plantcv.median_blur now allows the kernel size to be asymmetric (a two-element tuple) Fixed issues with Read the Docs rendering Documentation was updated to fix typos, command examples, etc. Some test data was reduced in size to shrink the memory footprint during build tests Fixed some package usage syntax to avoid future method deprecation issues Added color card mask helper function Added color card checker analysis function Added color card auto detection method (thanks to @bhive01 for the method inspiration) Improved code testing coverage to 98% Added method to read raw Bayer images Updated plantcv.fluor_fvfm to accept 8-bit images in addition to 16-bit images Added conda environment YAML configuration files for quick conda installatio