Use gandi API to get domain renewal dates

Closes: #134

update.py

@@ -18,6 +18,7 @@ import agenda.uk_holiday
 import agenda.waste_schedule
 from agenda import gwr
 
+
 config = __import__("config.default", fromlist=[""])
 
 
@@ -107,6 +108,20 @@ def update_thespacedevs() -> None:
     print(f"took {time_taken:.1f} seconds")
 
 
+def update_gandi() -> None:
+    """Retrieve list of domains from gandi.net."""
+    url = "https://api.gandi.net/v5/domain/domains"
+    headers = {"authorization": "Bearer " + config.GANDI_TOKEN}
+    filename = os.path.join(config.DATA_DIR, "gandi_domains.json")
+
+    r = requests.request("GET", url, headers=headers)
+    items = r.json()
+    assert isinstance(items, list)
+    assert all(item["fqdn"] and item["dates"]["registry_ends_at"] for item in items)
+    with open(filename, "w") as out:
+        out.write(r.text)
+
+
 def main() -> None:
     """Update caches."""
     now = datetime.now()