chore(deps): remove read-pkg-up

[XhmikosR]

Refs #3941.

Note:

Opening this for feedback. I have tried to make this foolproof, but it might not be 100% the same, for example you might not want to throw an error if JSON.parse fails here, so, I'll let you decide. :)

PS. I haven't checked if there's similar code in other parts of the codebase. If so, it's probably best abstracting this, using it everywhere and testing it properly.

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If this lands, the same should be made in the remaining 2 production packages that depend on read-pkg-up:

C:\Users\xmr\Desktop\cli>npm ls read-pkg-up
netlify-cli@8.9.0 C:\Users\xmr\Desktop\cli
+-- @netlify/build@26.1.3
| `-- read-pkg-up@7.0.1
`-- @netlify/framework-info@8.0.1
  `-- read-pkg-up@7.0.1

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Summary

Fixes #<replace_with_issue_number>

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[erezrokah]

Thanks @XhmikosR, I'm not sure we'd like to inline this dependency.
read-pkg-up is small, well maintained, comes with tests and types.

Also it uses read-pkg that has other benefits like data normalization, see https://github.com/sindresorhus/read-pkg#why

Closing this for now. Please comment if you think I got this wrong.