Point oxipng to patched version

Some upstream changes required for parallel build to work.

codecs/oxipng/pkg-parallel/squoosh_oxipng_bg.wasm.d.ts

@@ -1,11 +1,11 @@
 /* tslint:disable */
 /* eslint-disable */
-export function optimise(a: number, b: number, c: number, d: number): void;
 export function malloc(a: number): number;
 export function free(a: number): void;
 export function worker_initializer(a: number): number;
 export function start_main_thread(): void;
 export function start_worker_thread(): void;
+export function optimise(a: number, b: number, c: number, d: number): void;
 export const __wbindgen_export_0: WebAssembly.Memory;
 export function __wbindgen_malloc(a: number): number;
 export function __wbindgen_free(a: number, b: number): void;