Some DeprecationWarning in test suite with Python 3.14

[terjeros]

Runing test suite with Python 3.14 is somewhat noisy, following warnings are seen:

tests/test_insert_files.py: 12 warnings
  /builddir/build/BUILD/python-sqlite-utils-3.38-build/sqlite_utils-3.38/sqlite_utils/cli.py:3206: DeprecationWarning: datetime.date
time.utcfromtimestamp() is deprecated and scheduled for removal in a future version. Use timezone-aware objects to represent datetim
es in UTC: datetime.datetime.fromtimestamp(timestamp, datetime.UTC).
    "mtime_iso": lambda p: datetime.utcfromtimestamp(p.stat().st_mtime).isoformat(),
tests/test_insert_files.py: 12 warnings
  /builddir/build/BUILD/python-sqlite-utils-3.38-build/sqlite_utils-3.38/sqlite_utils/cli.py:3207: DeprecationWarning: datetime.date
time.utcfromtimestamp() is deprecated and scheduled for removal in a future version. Use timezone-aware objects to represent datetim
es in UTC: datetime.datetime.fromtimestamp(timestamp, datetime.UTC).
    "ctime_iso": lambda p: datetime.utcfromtimestamp(p.stat().st_ctime).isoformat(),
tests/test_recipes.py::test_dateparse_errors[None-parsedate]
  /usr/lib/python3.14/site-packages/_pytest/unraisableexception.py:85: PytestUnraisableExceptionWarning: Exception ignored on sqlite
3 callback <function Table.convert.<locals>.convert_value at 0x7fde5f4c2090>: None
  
  Traceback (most recent call last):
    File "/builddir/build/BUILD/python-sqlite-utils-3.38-build/sqlite_utils-3.38/sqlite_utils/db.py", line 2886, in convert_value
      return jsonify_if_needed(fn(v))
                               ~~^^^
    File "/builddir/build/BUILD/python-sqlite-utils-3.38-build/sqlite_utils-3.38/tests/test_recipes.py", line 77, in <lambda>
      fresh_db["example"].convert("dt", lambda value: getattr(recipes, fn)(value))
                                                      ~~~~~~~~~~~~~~~~~~~~^^^^^^^
    File "/builddir/build/BUILD/python-sqlite-utils-3.38-build/sqlite_utils-3.38/sqlite_utils/recipes.py", line 19, in parsedate
      parser.parse(value, dayfirst=dayfirst, yearfirst=yearfirst)
      ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "/usr/lib/python3.14/site-packages/dateutil/parser/_parser.py", line 1368, in parse
      return DEFAULTPARSER.parse(timestr, **kwargs)
             ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^
    File "/usr/lib/python3.14/site-packages/dateutil/parser/_parser.py", line 643, in parse
      raise ParserError("Unknown string format: %s", timestr)
  dateutil.parser._parser.ParserError: Unknown string format: invalid
  
    warnings.warn(pytest.PytestUnraisableExceptionWarning(msg))
tests/test_recipes.py::test_dateparse_errors[None-parsedatetime]
  /usr/lib/python3.14/site-packages/_pytest/unraisableexception.py:85: PytestUnraisableExceptionWarning: Exception ignored on sqlite