cache wasm-web

This improves start up time, I haven't benchmarked, but it definitely "feels" quicker.

src/transform.ts

@@ -4,14 +4,19 @@ import {
   parseSync,
   printSync,
   Program,
+  toFileUrl,
   transformSync,
 } from "./deps.ts";
+import { cache } from "https://deno.land/x/cache@0.2.13/mod.ts";
 import { TransformOptions } from "./types.ts";
 import { UltraVisitor } from "./ast/ultra.ts";
 import { ImportMapResolver } from "./importMapResolver.ts";
 import { VendorVisitor } from "./ast/vendor.ts";
 
-await initSwc("https://cdn.esm.sh/@swc/wasm-web@1.2.165/wasm_bg.wasm");
+const wasmFilepath = await cache(
+  "https://cdn.esm.sh/@swc/wasm-web@1.2.165/wasm_bg.wasm",
+);
+await initSwc(toFileUrl(wasmFilepath.path));
 
 const parserOptions: ParseOptions = {
   syntax: "typescript",