dfr uppercase for dataframe

Uppercase the strings in the column.

Signature

> dfr uppercase

Input/output types:

input	output
any	any

Examples

Modifies strings to uppercase

> [Abc aBc abC] | dfr into-df | dfr uppercase
╭───┬─────╮
│ # │  0  │
├───┼─────┤
│ 0 │ ABC │
│ 1 │ ABC │
│ 2 │ ABC │
╰───┴─────╯

Tips: Dataframe commands were not shipped in the official binaries by default, you have to build it with --features=dataframe flag