new: Add site_type to Region

[yec-akamai]

📝 Description

Expose a new field site_type to Region.

✔️ How to Test

tox
make TEST_CASE=test_get_regions testint

Manual Test:

1. In a sandbox environment, run the following:

import os

from linode_api4 import LinodeClient

client = LinodeClient(os.getenv("LINODE_TOKEN"))

regions = client.regions()

if len(regions) > 0:
    print(f"Region {regions[0].id} site type: {regions[0].site_type}")

2. Observe that region site type is in the output.

[zliang-akamai]

Works for me and looks good to me!

[lgarber-akamai]

LGTM!