BUG: core/generic/_update_inplace not resetting item_cache (GH5628)
Merge pull request #5631 from jreback/inplace_bug

BUG: core/generic/_update_inplace not resetting item_cache (GH5628)
CLN: expand groupby dispatch whitelist (GH5480)

- Create separate whitelists for SeriesGroupBy and DataFrameGroupBy objects
- Improve groupby whitelist testing