Remove backports.zoneinfo dependency (#65069)

homeassistant/package_constraints.txt

@@ -9,7 +9,6 @@ async_timeout==4.0.2
 atomicwrites==1.4.0
 attrs==21.2.0
 awesomeversion==22.1.0
-backports.zoneinfo;python_version<"3.9"
 bcrypt==3.1.7
 certifi>=2021.5.30
 ciso8601==2.2.0

homeassistant/util/dt.py

@@ -5,16 +5,11 @@ import bisect
 from contextlib import suppress
 import datetime as dt
 import re
-import sys
-from typing import Any, cast
+from typing import Any
+import zoneinfo
 
 import ciso8601
 
-if sys.version_info[:2] >= (3, 9):
-    import zoneinfo
-else:
-    from backports import zoneinfo
-
 DATE_STR_FORMAT = "%Y-%m-%d"
 UTC = dt.timezone.utc
 DEFAULT_TIME_ZONE: dt.tzinfo = dt.timezone.utc
@@ -48,8 +43,7 @@ def get_time_zone(time_zone_str: str) -> dt.tzinfo | None:
     Async friendly.
     """
     try:
-        # Cast can be removed when mypy is switched to Python 3.9.
-        return cast(dt.tzinfo, zoneinfo.ZoneInfo(time_zone_str))
+        return zoneinfo.ZoneInfo(time_zone_str)
     except zoneinfo.ZoneInfoNotFoundError:
         return None
 

requirements.txt

@@ -7,7 +7,6 @@ async_timeout==4.0.2
 attrs==21.2.0
 atomicwrites==1.4.0
 awesomeversion==22.1.0
-backports.zoneinfo;python_version<"3.9"
 bcrypt==3.1.7
 certifi>=2021.5.30
 ciso8601==2.2.0

setup.py

@@ -38,7 +38,6 @@ REQUIRES = [
     "attrs==21.2.0",
     "atomicwrites==1.4.0",
     "awesomeversion==22.1.0",
-    'backports.zoneinfo;python_version<"3.9"',
     "bcrypt==3.1.7",
     "certifi>=2021.5.30",
     "ciso8601==2.2.0",