1.9.3

Backport of Prepare for pandas 2.0 (#2434) onto 1.9.x (#2435)

* Prepare for pandas 2.0 (#2434)

* is_categorical -> is_categorical_dtype

* cat.replace(to_remove, np.nan) -> cat.remove_categories(to_remove)

* df1.append(df2) -> pd.concat([df1, df2])

* Series.iteritems -> Series.items

* Fix indexing a pandas object with a set in score genes

* Release notes

(cherry picked from commit 0692ef9ea30335b95f7e7f9aab7be856469d9f35)

* Fix anndata-dev test

* anndata-dev compatibility

* Prep 1.9.3

* Fix pr reference