Add standing orders for announcement feed

In terms of including the responsible parties in this:

So from a technical point of view:

• The announcement feed content is posted as a blog entry to: https://www.drupal.org/about/announcements/blog →
• So either a DA staff member or core team member could do that part.

BUT

• There is an extra step to publish the JSON feed (an extra safety net) - that only a DA engineering team member can do <-- so that's probably the role we should mention.

Historically I've been doing all this, but I'm not the only empowered to do so.

Thanks. I've updated the suggested content and made an MR.

Correct a link in the issue summary

Added one comment to the MR. Thanks!