Security Group for pods -ENI without IPv4 address in dual stack subnets

[happosade]

What would you like to be added:

We'd like to use security group for pods without assigning IPv4 address to ENI that's being created. Currently it seems like ENIs created to subnet has both IPv4 and IPv6 addresses. Subnet is dual stack.

Why is this needed:

We have migrated to dual stack subnets in order to avoid IPv4 exhaustion in VPCs, since our address space is somewhat limited. This feature request would allow nodes to be in dual stack, but keep the pods themselves in IPv6 only. This helps with IPv4 addressing, since there are way fewer addresses available compared IPv6 addresses.