Fix prop order

Signed-off-by: Šimon Brandner <simon.bra.ag@gmail.com>

src/Avatar.tsx

@@ -49,10 +49,10 @@ const resolveAvatarSrc = (client: MatrixClient, src: string, size: number) =>
 interface Props extends React.HTMLAttributes<HTMLDivElement> {
   bgKey?: string;
   src?: string;
-  fallback: string;
   size?: Size | number;
   className?: string;
   style?: CSSProperties;
+  fallback: string;
 }
 
 export const Avatar: React.FC<Props> = ({