change absolute path to relative so their compatible with yarn worksp…

[rulonder]

The previous absolute path was not compatible with yarn workspaces.
I have tested this on windows.
So now it works inside yarn workspaces. I also tested it standalone.

from:
#3031

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[MikeSuiter]

@rulonder I copied the change from your PR to my local install of createReactApp.js and tried to create-react-app in both a workspace and external and it fails with this error on Windows.

PS D:\Workspaces\React\workspace\packages> create-react-app app-e

Creating a new React app in D:\Workspaces\React\workspace\packages\app-e.

Installing packages. This might take a couple of minutes.
Installing react, react-dom, and react-scripts...

yarn add v1.2.1
[1/4] Resolving packages...
[2/4] Fetching packages...
warning Pattern ["react@16.0.0"] is trying to unpack in the same destination "C:\\Users\\suim01\\AppData\\Local\\Yarn\\cache\\v1\\npm-react-16.0.0-ce7df8f1941b036f02b2cca9dbd0cb1f0e855e2d" as pattern ["react@^16.0.0","react@^15 || ^16"]. This could result in a non deterministic behavior, skipping.
warning Pattern ["react-dom@16.0.0"] is trying to unpack in the same destination "C:\\Users\\suim01\\AppData\\Local\\Yarn\\cache\\v1\\npm-react-dom-16.0.0-9cc3079c3dcd70d4c6e01b84aab2a7e34c303f58" as pattern ["react-dom@^16.0.0","react-dom@^15 || ^16"]. This could result in a non deterministic behavior, skipping.
info fsevents@1.1.2: The platform "win32" is incompatible with this module.
info "fsevents@1.1.2" is an optional dependency and failed compatibility check. Excluding it from installation.
[3/4] Linking dependencies...
[4/4] Building fresh packages...
success Saved lockfile.
success Saved 6 new dependencies.
├─ app-a@0.1.0
├─ app-b@0.1.0
├─ app-e@0.1.0
├─ react-dom@16.0.0
├─ react-scripts@1.0.14
└─ react@16.0.0
Done in 11.41s.

Aborting installation.
Unexpected error. Please report it as a bug:
{ Error: Cannot find module '..\react-scripts\package.json'
    at Function.Module._resolveFilename (module.js:469:15)
    at Function.Module._load (module.js:417:25)
    at Module.require (module.js:497:17)
    at require (internal/module.js:20:19)
    at checkNodeVersion (C:\Users\suim01\AppData\Roaming\npm\node_modules\create-react-app\createReactApp.js:476:23)
    at getPackageName.then.then.then.packageName (C:\Users\suim01\AppData\Roaming\npm\node_modules\create-react-app\createReactApp.js:285:7)
    at process._tickCallback (internal/process/next_tick.js:109:7) code: 'MODULE_NOT_FOUND' }

Deleting generated file... node_modules
Deleting generated file... package.json
Deleting app-e / from D:\Workspaces\React\workspace\packages
Done.

Were there any other changes you had to do to get it to work? My workspace configuration looks similar to yours.

{
  "private": true,
  "workspaces": [
    "packages/*"
  ]
}

My CRA is version 1.4.1 and Yarn version 1.2.1