feat: add Options.env

[DiscreteTom]

With this feature, users can specify $PATH to locate the ripgrep bin.

import { ripGrep as rg } from 'ripgrep-js';
import * as path from "path";

const rgFolderPath = 'xxx';

rg('path/to/search', {
  string: 'xxx',
  env: {
    ...process.env,
    // https://github.com/nodejs/node/issues/34667#issuecomment-672863358
    [Object.keys(process.env).find((x) => x.toUpperCase() === "PATH")!]:
      process.env.PATH + path.delimiter + rgFolderPath,
  }
})