chore: v0.19.0

[lukapeschke]

No description provided.

[lukapeschke]

This release includes fixes #437 and fixes #303, based on the work in #434 (thanks @temaxuck and @stephenlf !).

Recap of changes:

• feat: add absolute index to column info #434 adds an absolute_index to ColumnInfo. It represents the index of a column in the excel file, whereas index is the index of a column in the calamine range. This is useful when the leftmost columns in a sheet are empty
• fix: use_columns no longer silently fails when leftmost columns are empty #438 builds on a that to properly handle ranges in the A:D form, by considering indices passed in use_columns as absolute indices. ⚠️ This is technically a breaking change for sheets starting with empty columns where use_columns was explicitly used with indices, but I'd say that this is the desired behavior in the vast majority of cases.
• fix: allow using use_columns with load_table when column_names is not specified #437 allows to use use_columns with load_table. This is a bug that was originally spotted in polars and that we missed, so it was unfortunately open for quite some time 😕

@alexander-beedie This should remove the need for the workaround in pola-rs/polars#24965 .

Also, the new absolute_index attribute should allow to implement "drop_empty_cols" in polars with fastexcel: since the absolute index of the first column is known, empty columns can be added to the front of the dataframe if needed.

[lukapeschke]

depends on #440