mix-manifest.json

{
    "/dist/js/app.js": "/dist/js/app.js",
    "/dist/css/app.css": "/dist/css/app.css",
    "/dist/js/background.js": "/dist/js/background.js",
    "/dist/manifest.json": "/dist/manifest.json",
    "/dist/index.html": "/dist/index.html"
}