Upgrade dependencies for CVE-2020-7660

[captain-kark]

When using this project as a template, I was given security warnings concerning GHSA-hxcc-f52p-wc94

What I did to fix this after generating a new project from this template:

mochajs/mocha#4375

• update

  worker-typescript-template/package.json

  Line 21 in 9a1574a

  "mocha": "^8.0.1",

    "mocha": "^8.1.0",

webpack/webpack#11309

• Security advisory for serialize-javascript package webpack/webpack#11309 (comment)

Afterwards, the example npm test and npm run build succeeded.