Add --sheet parameter to describe command for XLSX

[vviers]

Overview

Hey there 👋🏼 thanks for the great package !

One small improvement to my quality of life as a developper would be to have the option to easily point to a specific sheet within xls/ods files when using the frictionless describe command.

I know frictionless describe --dialect '{"excel": {"sheet": "my sheet"}}' Tables.xlsx works, but since the extract and validate commands have the handy --sheet parameter, I figured the same could be added to the describe command as well ?

Happy to implement this and make a PR if you think that's useful !

[shashigharti]

Thanks! @vviers, we will add.