Do not use datetime.utcnow() that is deprecated in Python 3.12 (#972)

* Do not use datetime.utcnow() that is deprecated in Python 3.12

Import session.utcnow() into utils instead of reimplementing it

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Remove unneeded noqa

* Add noqa

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: David Brochart <david.brochart@gmail.com>
Co-authored-by: Steven Silvester <steven.silvester@ieee.org>

jupyter_client/session.py

@@ -197,7 +197,7 @@ def default_secure(cfg: t.Any) -> None:  # pragma: no cover
 
 def utcnow() -> datetime:
     """Return timezone-aware UTC timestamp"""
-    return datetime.utcnow().replace(tzinfo=utc)  # noqa
+    return datetime.now(utc)
 
 
 # -----------------------------------------------------------------------------

jupyter_client/utils.py

@@ -4,10 +4,11 @@
 - vendor functions from ipython_genutils that should be retired at some point.
 """
 import os
-from datetime import datetime, timedelta, tzinfo
 
 from jupyter_core.utils import ensure_async, run_sync  # noqa: F401  # noqa: F401
 
+from .session import utcnow  # noqa
+
 
 def _filefind(filename, path_dirs=None):
     """Find a file by looking through a sequence of paths.
@@ -84,35 +85,3 @@ def _expand_path(s):
     if os.name == "nt":
         s = s.replace("IPYTHON_TEMP", "$\\")
     return s
-
-
-# constant for zero offset
-ZERO = timedelta(0)
-
-
-class tzUTC(tzinfo):  # noqa
-    """tzinfo object for UTC (zero offset)"""
-
-    def utcoffset(self, d):
-        """Compute utcoffset."""
-        return ZERO
-
-    def dst(self, d):
-        """Compute dst."""
-        return ZERO
-
-
-UTC = tzUTC()  # type:ignore[abstract]
-
-
-def utc_aware(unaware):
-    """decorator for adding UTC tzinfo to datetime's utcfoo methods"""
-
-    def utc_method(*args, **kwargs):
-        dt = unaware(*args, **kwargs)
-        return dt.replace(tzinfo=UTC)
-
-    return utc_method
-
-
-utcnow = utc_aware(datetime.utcnow)