Allow patch level differences in preflight check

Is this a bug report?

Yes, I am getting an eslint preflight check error hen I don’t think I should be.

Did you try recovering your dependencies?

Yes, I’ve tried deleting the package-lock and rebuilt some stuff, but this issue seems pretty clearcut

Which terms did you search for in User Guide?

I searched for eslint there and in the issues but this is for the new release and I dont’ think thats updated yet

Environment

(paste the output of the command here)

Steps to Reproduce

To reproduce

create-react-app craeslint
cd craeslint
npm install eslint@5.6.1

I get the following. I don’t think this is correct - a difference in patch version shouldn’t cause the preflight check to fail, should it? (Also react-scripts should probably update their eslint version)

> craeslint@0.1.0 test /Users/gmauer/code/craeslint
> react-scripts test


There might be a problem with the project dependency tree.
It is likely not a bug in Create React App, but something you need to fix locally.

The react-scripts package provided by Create React App requires a dependency:

  "eslint": "5.6.0"

Don't try to install it manually: your package manager does it automatically.
However, a different version of eslint was detected higher up in the tree:

  /Users/gmauer/code/craeslint/node_modules/eslint (version: 5.6.1) 

Expected Behavior

tests run fine - there is only a difference in patch level of eslint

Actual Behavior

I get the following

> craeslint@0.1.0 test /Users/gmauer/code/craeslint
> react-scripts test


There might be a problem with the project dependency tree.
It is likely not a bug in Create React App, but something you need to fix locally.

The react-scripts package provided by Create React App requires a dependency:

  "eslint": "5.6.0"

Don't try to install it manually: your package manager does it automatically.
However, a different version of eslint was detected higher up in the tree:

  /Users/gmauer/code/craeslint/node_modules/eslint (version: 5.6.1) 

[AdamLantz]

I wonder if adding some specificity to the skip variable could solve the issue (e.g. SKIP_PREFLIGHT_CHECK=eslint).

Rather than saying you’re knowingly skipping all the preflight checks, you could specify which preflight checks to skip.

[Timer]

Right now, this is intentional. We want to find an exact version match. We’ve actually never supported installing ESLint alongside Create React App, so this warning is fine IMO.

For now, please match the version or disable the check with the suggested environment variable.