`prepare-release.sh` script uses `standard-version` which is now deprecated

[Zidious]

We use standard-version in prepare-release.sh to version our packages, unfortunately it's now deprecated.

We should look into Lerna for versioning and changelog generation. We can create a lerna.json that will contain:

{
  "version": "4.7.0",
  "packages": ["selenium", "playwright"]
}

We can then use the lerna version command used in axe-core-npm to version and generate changelogs