feat: add support for IPv6 and dual-stack EFS mount targets @ngoyal16 (#163)
## what- Added support for dual-stack (IPv4 and IPv6) EFS mount targets.
- Introduced mount_target_ip_address_type variable to select between IPV4_ONLY, IPV6_ONLY, and DUAL_STACK.
- Introduced mount_target_ipv6_address variable to specify a custom IPv6 address.
- Updated aws_efs_mount_target resource to utilize the new variables and apply conditional logic for IP assignment.
- Added mount_target_ipv6_addresses output to expose the assigned IPv6 addresses.
why
- The new version of AWS EFS supports dual-stack endpoints, allowing for better compatibility with IPv6-enabled environments.
- Users need the ability to configure the IP address type and provide specific IPv6 addresses if required.