Feature Request: Add 'once' to the esbuild-plugin-copy

[jrmyio]

Currently the copy plugin runs on every build (during watch). However, in most situations its just fine to only do the copy on the first cycle to prevent unnecessary resources and disk writing being done on each code change.

I suggest expanding the options to:

export interface Options {
  // assets pair to copy
  assets: MaybeArray<AssetPair>;
  // start copy on onStart hooks instead of onEnd
  // default: false
  copyOnStart: boolean;
  // verbose logging
  // default: true
  verbose: boolean;
  // extra globby options for paths matching, will be passed to globby directly
  globbyOptions: GlobbyOptions;
  // only run the copy once
  // default: false
  once: boolean;
}

[linbudu599]

This is supported in latest version 1.0.1 now, please refers to esbuild-plugin-copy#configuration