Fix: npm run format

[NeverMendel]

According to my understanding the script format: prettier --write 'src/**/*.js' doesn't need the apices.

The old syntax generated the following error:

> [email protected] format C:\Users\[USER]\[PATH]\store.gatsbyjs.org
> prettier --write 'src/**/*.js'

[error] No matching files. Patterns tried: 'src/**/*.js' !**/node_modules/** !./node_modules/** !**/.{git,svn,hg}/** !./.{git,svn,hg}/**
npm ERR! code ELIFECYCLE
npm ERR! errno 2
npm ERR! [email protected] format: `prettier --write 'src/**/*.js'`
npm ERR! Exit status 2
npm ERR! 
npm ERR! Failed at the [email protected] format script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     C:\Users\[USER]\AppData\Roaming\npm-cache\_logs\2019-02-14T20_06_48_090Z-debug.log

[jlengstorf]

Oh, interesting. Looks like it works with or without on Mac, but not on Windows. Thanks for this!