Block Library: Column: Add step attribute to column width range input

Without this attribute value, if a user would enter a decimal value in the input range, the result of Element#checkValidity (in RangeControl) would be `false`, thus making it difficult/impossible to enter non-whole-number widths (e.g. `33.3`).

There's a balance here between the effects of step, where ArrowUp/ArrowDown will now increment/decrement in smaller intervals than previously. This becomes further problematic if we want to support smaller decimal values (e.g. 33.33). A potential alternative would be to change the validation behavior of RangeControl to use a custom validation procedure in place of `Element#checkValidity`.

packages/block-library/src/column/edit.js

@@ -48,6 +48,7 @@ function ColumnEdit( {
 						} }
 						min={ 0 }
 						max={ 100 }
+						step={ 0.1 }
 						required
 						allowReset
 					/>