Duration division, multiplication and mod broken for month lengths.

[gazpachoking]

• I am on the latest Pendulum version.
• I have searched the issues of this repo and believe that this is not a duplicate.

• OS Version: Windows 11
• Pendulum version: 3.0.0

Issue

When doing math on Duration objects, months are ignored. This is because it uses the _to_microseconds method which ignores the months attribute.

pendulum/src/pendulum/duration.py

Lines 356 to 357 in 3e3fec6

	def _to_microseconds(self) -> int:
	return (self._days * (24 * 3600) + self._seconds) * 1000000 + self._microseconds

e.g. :

>>> pendulum.Duration(years=1)/pendulum.Duration(months=1)
Traceback (most recent call last):
  File "C:\Program Files\JetBrains\PyCharm 2022.2.2\plugins\python\helpers\pydev\pydevconsole.py", line 364, in runcode
    coro = func()
  File "<input>", line 1, in <module>
  File "C:\Users\chase\PycharmProjects\Flexget\py310\lib\site-packages\pendulum\duration.py", line 419, in __truediv__
    float, usec / other._to_microseconds()  # type: ignore[attr-defined]
ZeroDivisionError: division by zero

>>> pendulum.Duration(months=1)*3.0
Duration()

[Benji19967]

Duration only supports full months and years, hence floating-point multiplication is not supported.

@sdispater @Secrus I see two options here:

• Raise an error when floating-point multiplication is applied on a Duration with years>0 and/or months>0.
• Round up or down to the nearest integer as is done with __truediv__

  pendulum/src/pendulum/duration.py

  Lines 431 to 439 in 3e3fec6

  	if isinstance(other, float):
  	a, b = other.as_integer_ratio()
  	return self.__class__(
  	0,
  	0,
  	_divide_and_round(b * usec, a),
  	years=_divide_and_round(self._years * b, a),
  	months=_divide_and_round(self._months, other),