Private Space network CIDR ranges are now configurable when creating space

Change effective on 12 September 2018

When creating a Private Space using the Heroku CLI, you can now provide the CIDR ranges to be used for the dyno and data VPCs associated with the Private Space:

$ heroku spaces:create --cidr --data-cidr --space my-space

The CIDR ranges have to be from RFC 1918 blocks. The dyno VPC (cidr) has to be a /16 block. The data VPC (data-cidr) has to be at least a /20 block.

See the Private Space Dev Center article for details.