Do not allow 'latest' when installing npm packages

[gaitat]

🐛 bug report

Preflight Checklist

• I have read the Contributing Guidelines for this project.
• I agree to follow the Code of Conduct that this project
  adheres to.
• I have searched the issue tracker for an issue that matches the one I want
  to file, without success.

Description of the problem

codesandbox is a great resource for web developers, by providing a place to write working code examples. There is no doubt about that.
By allowing latest as an install option for an npm package allows a developer to quickly write a working example.
But 6 months down that road the example doesn't work any more because latest means something different than what the developer intended. As a result the examples living in codesandbox slowly become stale and non-working.

How has this issue affected you? What are you trying to accomplish?

As I mentioned, codesandbox is a great resource. I visit it very often to learn from the examples. But they don't always work.

To Reproduce

Open the example sandbox and observe that it doesn't work any more because of using the latest npm packages.

Link to sandbox: example

Not my sandbox.

Your Environment

Software	Name/Version
Сodesandbox	latest
Browser	chrome
Operating System	Windows 10