vue-cli@5 support

[SnosMe]

Hello, I'm trying to use it with v5.0.0-alpha.4

electron:serve works without any issues even in complex project (https://github.com/SnosMe/awakened-poe-trade/), unfortunately electron:build (tested in clean project) results in

$ vue-cli-service electron:build
 INFO  Bundling render process:

-  Building modern bundle for production... ERROR  Vue CLI build failed. Please resolve any issues with your build and try again.
error Command failed with exit code 1.

[williamweckl]

Same issue here, it is the only thing preventing me to use webpack 5.

[nklayman]

This is a bug with vue cli v5 rather than this plugin. I created an issue on their repo: vuejs/vue-cli#6312.

Since this plugin sets the build dest to dist_electron, it triggers this bug.