[DOC] RAPIDS 22.06 Release Blog Outline

[caryr35]

Provide bullet point list of major user facing changes to Sophie Watson by the end of **burn down**

[AjayThorve]

Major User facing changes occured in the PRs #359, #366

• Added native support for dask_cudf dataframes. Seamless integration results in a dask_cudf.DataFrame working as a drop-in replacement for a cudf.DataFrame
• added unseleced_alpha parameter to all datashader charts, which displays unselected data as the same color palette but transparent (default alpha=0.2)
• added binary data transfer support for choropleth charts, which results in a much smoother experience interacting with the choropleth charts, since only updated data is being sent as binary instead of entire spec json string on each interaction.
• choropleth interactions are more stable, and edge cases where it sometimes failed rendering a lot of nan values, has been resolved.
• Added a bunch of dask_cudf notebooks and performance benchmarks on a DGX machine (8*32GB GV100)

cc @exactlyallan