[ENH] Extend column selection to non-strings (#1106)

* simplify column selection logic for sequences

* make base object singledispatch generic

* add fixtures for dates and numbers

* cleanup tests; added more; clean up logic in slice selection...

* changelog

* updates to pivot_longer

* tests fix

* tests added

* fix notebook

* fix test fails

* Fix spelling

* fix test fail

* updates based on feedback

* simplify pivot column selection branching

Co-authored-by: Eric Ma <[email protected]>

Author: samukweku

CHANGELOG.md

@@ -4,7 +4,8 @@
 
 -   [DOC] Updated developer guide docs.
 -   [ENH] Allow column selection/renaming within conditional_join. #1102 @samukweku.
--   [EHN] New decorator `deprecated_kwargs` for breaking API. #1103 @Zeroto521
+-   [ENH] New decorator `deprecated_kwargs` for breaking API. #1103 @Zeroto521
+-   [ENH] Extend select_columns to support non-string columns. #1105 @samukweku
 
 ## [v0.23.1] - 2022-05-03