Realization conjecture for finite groups as Galois groups of coverings

Let $k(x)$ be the function field of the projective line, and let $E$ be a finite regular Galois extension of $k(x)$ with Galois group $G$. Equivalently, the inclusion $k(x)\hookrightarrow E$ defines a ramified Galois covering $C\to\mathbb{P}^{1}$ over $k$ with Galois group $G$. Realization conjecture. Every finite group $G$ occurs as the Galois group of such a covering. This is a realization problem for finite groups as Galois groups of regular function-field extensions, and the supplied text does not state whether the claim is known or open.