`CI=true create-next-app --ts` sets up project using JS instead of TS

[tmadeira]

Verify canary release

• [X] I verified that the issue exists in the latest Next.js canary release

Provide environment information

Operating System:
  Platform: linux
  Arch: x64
  Version: #1 SMP PREEMPT_DYNAMIC Thu, 03 Nov 2022 18:01:58 +0000
Binaries:
  Node: 14.21.0
  npm: 8.19.2
  Yarn: 1.22.19
  pnpm: N/A
Relevant packages:
  next: 13.0.2
  eslint-config-next: 13.0.2
  react: 18.2.0
  react-dom: 18.2.0

What browser are you using? (if relevant)

No response

How are you deploying your application? (if relevant)

No response

Describe the Bug

Using npx create-next-app@latest --ts my-app does not work in continuous integration environments (i.e., if CI env var is set). The CLI simply ignores the --ts flag (https://github.com/vercel/next.js/blob/canary/packages/create-next-app/index.ts#L160).

Expected Behavior

Project should be bootstraped with TypeScript.

(It's okay to default to JavaScript to not break existing CI expecting JS, but if the command line argument --ts is given explicitly then create-next-app should install TypeScript packages and use TypeScript.)

Link to reproduction

CI=true npx create-next-app@latest --ts my-app

To Reproduce

1. Run CI=true npx create-next-app@latest --ts my-app
2. create-next-app should install TypeScript packages, but it doesn't.