Postinstall script can fail on windows during install

[steven-hoffman-jomashop]

Description

Postinstall script can fail on windows during install

Expected outcome

postinstall script does not fail

Actual outcome

postinstall script fails

Steps to reproduce

run in windows: yarn run postinstall || echo 'Fail'

• npm appears to handle the error (or otherwise does not fail)

Possible Fix

Wrap existing postinstall script in sh -c '...'
"postinstall": "sh -c 'FILE=\"$(npm root)/@reallyland/tools/postinstall.sh\"; if [ -f \"$FILE\" ]; then sh \"$FILE\"; fi'",
This will still require sh for install, but a user can have that on the path.
(You could also convert to what pure-js does; which is to use a node script, here that can just spawn back to sh)