Update caldav to 2.1.0 (home-assistant#156166)

Author: dotlambda

homeassistant/components/caldav/manifest.json

@@ -6,5 +6,5 @@
   "documentation": "https://www.home-assistant.io/integrations/caldav",
   "iot_class": "cloud_polling",
   "loggers": ["caldav", "vobject"],
-  "requirements": ["caldav==1.6.0", "icalendar==6.3.1"]
+  "requirements": ["caldav==2.1.0", "icalendar==6.3.1", "vobject==0.9.9"]
 }

requirements_all.txt

@@ -211,7 +211,6 @@ def from_dict(cls, data: PackageMetadata) -> PackageDefinition:
     "aiocache": AwesomeVersion(
         "0.12.3"
     ),  # https://github.com/aio-libs/aiocache/blob/master/LICENSE all rights reserved?
-    "caldav": AwesomeVersion("1.6.0"),  # None -- GPL -- ['GNU General Public License (GPL)', 'Apache Software License']  # https://github.com/python-caldav/caldav
 }
 # fmt: on