[from 1.4 to 1.5.2] build doesn't build, it act like dev mode without assets

[Martin Kinoo]

✦ ❯ yarn run build
yarn run v1.22.10
$ node ./src/cleanPublic.js && npm run build:rollup && npm run build:html
 Clearing out public folder.

> opo-website@2.0.0 build:rollup
> rollup -c

CSS file not found in /home/equinox/Programming/opo/website/public/_elderjs/assets
Elder.js using rollup in production mode.
[...]
created public/_elderjs/svelte in 8.7s
> Elder.js running on http://localhost:3000

localhost:3000: console (firefox):

....
GET http://localhost:3000/5017/1623418122-icon-tarifs.svg
....

[Nick Reese]

@kiuKisas Fixed bad logic to check if rollup was in dev mode. Had || instead of &&.