add support for custom resolver

This release adds support for custom using a custom resolver. Specifically, a yarn PnP resolver can be passed to esmock, so that yarn PnP moduleIds can be resolved.

• update resolver to latest version, slightly faster with fewer loops
• add support for resolver configuration option

const modulePnP = await esmock('../src/parent.js', {
  '../src/PnPchild.js' : () => ['a', 'b']
}, null, {
  resolver: pnpapi.resolveRequest
})