Release v0.10.0

This release contains no breaking changes regarding the public XLSX API.

There's a breaking change regarding Cell struct: formula field changed type from String to AbstractFormula.

There's a breaking change regarding TableRowIterator struct: added field keep_empty_rows.

• Fixes row formatting that was previously lost (#227) (@best4innio)
• Add keep_empty_rows kwarg (#220) (@rben01)
• add colon indexing (#216) (@BeastyBlacksmith, @divbyzerofordummies)
• Docs review (#229) (@goggle)