Define a function make_pixel that consumes a string (representing one of four possible colors) and produces a Pixel.

A Pixel is a dataclass with three float fields: red, green, and blue. These float will go from 0.0 (dark) to 1.0 (light).

The four possible colors are "yellow" (full red and green, zero blue), "cyan" (full green and blue, zero red), "magenta" (full red and blue, zero green), or "black" (zero red, green, and blue). Any other string should produce a Pixel with all fields set to 1 (aka, white).