chore(examples): corrected lerna config so that mocha doesn't get hoisted
chore(examples): corrected lerna config so that mocha doesn't get hoisted

Hoisting mocha can prevent it from correctly recognising @serenity-js/mocha reporter, and break the
example projects under `./examples`

jan-molak/serenity-js,jan-molak/serenity-js,jan-molak/serenity-js,jan-molak/serenity-js