TestTimestamp.test_iso_format: Ensure t1.microsecond is not 0
TestTimestamp.test_iso_format: Ensure t1.microsecond is not 0

Bug: T199179
Change-Id: I2303f18f2f73922a0988e7806a945f06f78a61cb

PersianWikipedia/pywikibot-core,wikimedia/pywikibot-core,wikimedia/pywikibot-core