Resolving vertx dependency issues with webpack

[trylaarsdam]

What I’ve changed:
In /lib/env.js, the vertx require statement now uses @vertx/core, which is the node package for vertx. This resolves an issue when using webpack (see #482)
package.json has also been updated to include @vertx/core as a dependency.

[o0101]

please merge, as the workaround involves:

new webpack.NormalModuleReplacementPlugin(
  /^vertx/,
  '@vertx/core',
)

And npm i --save-dev @vertx/core

from: https://stackoverflow.com/a/71458295/10283964