Disable postcss config file when using inline config

[egoist]

What problem does this feature solve?

I manually load postcss config from its config file and set postcss in vue loader options, but vue-loader will also load it and merge inline config with config file so it leads to duplicated plugins.

btw, postcss-loader does not use config file when inline config is set.

What does the proposed API look like?

Maybe this should be the default behavior, or we can introduce an option for this.

[barraponto]

Agreed. It would be very useful for neutrino-middleware-vue.

[barraponto]

btw, can we close in favor of #654 ?