Update deno version from v0.21 -> v1.0.0 in usage tests

Because it seems the standard library for v0.21 that was used in the
usage tests before has been removed, it returns 404 now..

.github/workflows/verify.yml

@@ -96,9 +96,9 @@ jobs:
 
     steps:
       - uses: actions/checkout@v1
-      - uses: denolib/setup-deno@v1
+      - uses: denolib/setup-deno@master
         with:
-          deno-version: 'v0.23.0'
+          deno-version: 'v1.0.0'
       - run: deno --version
       - run: deno test --allow-net=deno.land test/module-systems/deno-test.ts
 

test/module-systems/deno-test.ts

@@ -1,5 +1,4 @@
-import { test } from "https://deno.land/std@v0.21.0/testing/mod.ts";
-import { assertEquals } from "https://deno.land/std@v0.21.0/testing/asserts.ts";
+import { assertEquals } from "https://deno.land/std@v0.51.0/testing/asserts.ts";
 import mustache from "../../mustache.mjs";
 
 const view = {
@@ -9,7 +8,7 @@ const view = {
   }
 };
 
-test(function canUseMustache() {
+Deno.test("can use mustache", () => {
   assertEquals(
     mustache.render("{{title}} spends {{calc}}", view),
     "Joe spends 6"