fix: build path & 404 error in production

[gurvancampion]

Fixes:

• https://github.com/caoxiemeihao/nuxt-electron/issues/1
• Probably https://github.com/caoxiemeihao/nuxt-electron/issues/4 too

On another note, I think it would be better to follow the Nuxt module author guide (links below) so the nuxt community can contribute to it and we could later ask to move the repository to https://github.com/nuxt-modules. Let me know what you think, I could help you when I have time but it would changes the current repository structure.

Nuxt module author guide:

• https://nuxt.com/docs/guide/going-further/modules
• (Chinese) https://nuxt.com.cn/docs/guide/going-further/modules/