fix: unique filename for temporary script files

[jlarmstrongiv]

Use unique filenames for temporary script files to avoid npm throwing text file busy errors

Switch from Date.now() to crypto.randomBytes(4).toString('hex')

References

Fixes #91
Closes #91

Code References

run-script/lib/make-spawn-args.js

Line 33 in 6493397

const fileName = escape.filename(`${event}-${Date.now()}`)

https://github.com/npm/cli/blob/9d6f3f9c410753bf9412ddfeac6a000feccd14f0/lib/npm.js#L447-L448

[jlarmstrongiv]

@nlf whoops, didn’t mean to open another pull request. Resolves suggestions #92 (review)