Upgrade Python syntax to 3.11+

Author: hugovk

.ruff.toml

@@ -1,4 +1,4 @@
-target-version = "py310"
+target-version = "py311"
 fix = true
 output-format = "full"
 line-length = 88

_tools/generate_release_cycle.py

@@ -101,7 +101,7 @@ def __init__(self, *, limit_to_active=False, special_py27=False) -> None:
 
     def write_csv(self) -> None:
         """Output CSV files."""
-        now_str = str(dt.datetime.now(dt.timezone.utc))
+        now_str = str(dt.datetime.now(dt.UTC))
 
         versions_by_category = {"branches": {}, "end-of-life": {}}
         headers = None