Stop importing as index.js to make esm.sh happy

It seems that `esm.sh` strips `index.js` from the import path while
bundling. This causes wrong `import "dist.js"` to be generated.

Close #335

Author: kateinoigakukun

packages/npm-packages/ruby-wasm-wasi/src/browser.ts

@@ -1,5 +1,6 @@
 import { Fd, WASI } from "@bjorn3/browser_wasi_shim";
-import { RubyVM, consolePrinter } from "./index.js";
+import { consolePrinter } from "./console.js";
+import { RubyVM } from "./vm.js";
 
 export const DefaultRubyVM = async (
   rubyModule: WebAssembly.Module,