Cannot create a firewall/various outbound rules via terraform with port_range "all" specified in outbound rule config

hi there - i tried to launch a firewall from terraform, but it doesn't really work yet 100%. terraform's documentation basically copies digitalocean's documentation verbatim, which states that the use of ```port_range``` is optional, and that ```all``` can be used to include all ports.

the api docs state this should be possible: [https://developers.digitalocean.com/documentation/v2/#add-rules-to-a-firewall](url)

the only way i could get it to work (creating a digitalocean firewall from scratch using terraform), was to setup the firewall config as you would normally (using ```all``` *does* work for ```port_range``` on inbound rules). comment out the entire ```outbound_rule``` block. run ```terraform plan``` then ```terraform apply``` and it will create the firewall.

here's the hcl that i'm using to create the firewall with terraform.

```
resource "digitalocean_firewall" "fwtest" {
name = "fwtest"
droplet_ids = []
tags = []

inbound_rule = [
{
protocol = "tcp"
port_range = "80"
source_addresses = ["1.2.3.4/32"]
},
{
protocol = "tcp"
port_range = "443"
source_addresses = ["1.2.3.4/32"]
},
{
protocol = "tcp"
port_range = "all"
source_addresses = ["1.2.3.4/32"]
}
]

/* outbound_rule = [
{
protocol = "icmp"
port_range = "0"
destination_addresses = ["0.0.0.0/0", "::/0"]
},
{
protocol = "tcp"
port_range = "0"
destination_addresses = ["0.0.0.0/0", "::/0"]
},
{
protocol = "udp"
port_range = "0"
destination_addresses = ["0.0.0.0/0", "::/0"]
}
] */
}
```

next, add the three outbound rules from the digitalocean web console.


now **uncomment** the ```outbound_rule``` block and run ```terraform refresh```. also worth noting - any inbound rules created from terraform using ```port_range = "all"``` will need to be **changed back** to ```port_range = "0"``` in order to make terraform happy.

if your outbound rules are setup like the hcl config here, ```terraform plan``` should now be green with no changes to be made.

so something is not quite right when adding rules via the api with the use of "all" to give sources/tags full access to whatever the protocol specified.