Apply formatting to num seconds

[aguinane]

Resolves issue #432

[mergify]

⚠️ No release notes detected. Please make sure to use reno to add a changelog entry.

[aguinane]

Updated with %.3g instead or %0.3f as the default.

[asqui]

This latest change deviates from the default format for after_log():

tenacity/tenacity/after.py

Lines 31 to 35 in e2482a6

	def after_log(
	logger: "logging.Logger",
	log_level: int,
	sec_format: str = "%0.3f",
	) -> typing.Callable[["RetryCallState"], None]:

Should we update that too, so that the two are consistent?

[jd]

Sounds like a good idea.

[aguinane]

Made the change to after_log also.