[BuildStream] Monthly irc meeting - confirmation of hiatus

[Laurence Urhegyi <laurence urhegyi codethink co uk>]

Hi all,

Seems we had at least one person turning up for the monthly irc meeting 
last week and wondering why no-one else was there, so I thought I'd send 
a mail to confirm:

Update: as of summer 2019 these meetings have temporarily stopped - the 
number of points worthy of discussion was small enough to instead just 
use the mailing list.

I've also removed the Google calendar invite from the BuildStream 
Community calendar and updated the Wiki page here:

https://wiki.gnome.org/Projects/BuildStream/Monthly-Meeting#preview

Regards,
Laurence