Update and clean up AssemblyScript example (#4233)

* Update and clean up AssemblyScript example

* Remove wasm build files

* Remove wasm source files

docs/assemblyscript-hello-world/package.json

@@ -4,15 +4,16 @@
   "description": "Hello world in Wasi with AS and as-wasi",
   "main": "index.js",
   "scripts": {
-    "build": "asc wasi-hello-world.ts -b wasi-hello-world.wasm",
-    "wasmtime": "wasmtime wasi-hello-world.wasm"
+    "build": "asc wasi-hello-world.ts --target helloworld",
+    "wasmtime": "wasmtime ./build/wasi-hello-world.wasm"
   },
   "author": "Aaron Turner",
+  "contributors": [
+    "Jairus Tanaka (JairusSW)"
+  ],
   "license": "MIT",
   "devDependencies": {
-    "assemblyscript": "^0.19.10"
+    "assemblyscript": "^0.20.7"
   },
-  "dependencies": {
-    "as-wasi": "^0.4.6"
-  }
+  "dependencies": {}
 }