docs: specify minimun version of npm to run command in subproject

[cuichenli]

Signed-off-by: Cuichen Li cuichli@cisco.com

Which problem is this PR solving?

The CONTRIBUTING document did not specify clearly the minimum version of npm and I am getting errors when trying to run lint in subprojects says can not find eslint. Turns out I was using npm@6.x, which does not have the algorithm to find binary in parent node_modules. By upgrading it to at least 7.x can fix the issue.

This may be one edge case (I do not know how many people are still using this version nowadays). But by using nvm to install node14 we would get npm@6.x.

[codecov]

Codecov Report

Merging #2728 (edfd205) into main (ed043be) will not change coverage.
The diff coverage is n/a.

❗ Current head edfd205 differs from pull request most recent head 9d7783e. Consider uploading reports for the commit 9d7783e to get more accurate results

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[dyladan]

I have not had this issue with npm 6

[dyladan]

ah i see when you run from directly within the directory

[legendecas]

Thank you for the work!