Consider setting pm2-logroate on by default

[NunoSempere]

I've repeatedly run out of memory on my local server, enough that it's become a bit irritating. I eventually set up some hacky reminders to run pm2 flush, but decided to look into this properly, and found that pm2-logrotate solves this problem completely. Maybe consider setting it on by default with some sensible parameters? Alternatively, consider setting a more prominent reminder in the README that pm2 can end up filling your whole memory.

I'm hugely appreciative of pm2 in general, but I thought I'd report on this.