Fix checkIfUp option

[Huntedpix]

Hello !

I've just migrate my project from aemsync 4.0.3 to 5.0.5, and I've notice that the option checkIfUp is always returning an error.

I've search why and found out that fetch doesn't allow to embed credentials into the url.

TypeError: http://admin:admin@localhost:4502/ is an url with embedded credentials.
    at new Request (ui.frontend/node_modules/node-fetch/src/request.js:60:10)

To minimize the change, I've update the code to remove the credential from the target and pass it as headers.

[gavoja]

Use new URL() instead of regular expression:

const url = new URL(target)
const auth = `${url.username}:${url.password}`
url.username = ''
url.password = ''
const res = await fetch(url.toString(), {
  headers: { 'Authorization':  `Basic ${btoa(auth) }` }
}