Add Google Read Aloud Bot

[cspeer]

Description

Hi,

I'd love to see the Google Read Aloud Bot added to the list of bots.
Even though it's a trigger fetcher according to Google it accounts for quite a bit of requests on our site.

Here's an exmaple ua:
Mozilla/5.0 (Linux; Android 7.0; SM-G930V Build/NRD90M) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.125 Mobile Safari/537.36 (compatible; Google-Read-Aloud; +https://support.google.com/webmasters/answer/1061943)

If push requests are welcome, I'm happy to do it myself.

Thanks!