chore: include ms in transforming datetime to UTC string #436

Job	Run time
Lint check / Lint check (3.12)	10s
Lint check / Lint check (3.10)	11s
Unit tests / Unit tests (ubuntu-latest, 3.11)	26s
Lint check / Lint check (3.13)	11s
Lint check / Lint check (3.11)	15s
Unit tests / Unit tests (ubuntu-latest, 3.10)	21s
Unit tests / Unit tests (windows-latest, 3.10)	51s
Unit tests / Unit tests (windows-latest, 3.11)	43s
Unit tests / Unit tests (ubuntu-latest, 3.12)	22s
Unit tests / Unit tests (windows-latest, 3.12)	41s
Unit tests / Unit tests (ubuntu-latest, 3.13)	28s
Unit tests / Unit tests (windows-latest, 3.13)	51s
Type check / Type check (3.12)	17s
Type check / Type check (3.10)	17s
Type check / Type check (3.13)	20s
Type check / Type check (3.11)	15s
Docs check / Docs check	58s
Async dostrings check / Async docstrings check	16s
Integration tests / Integration tests (3.11)	33s
Integration tests / Integration tests (3.12)	46s
Integration tests / Integration tests (3.13)	49s
Integration tests / Integration tests (3.10)	32s
	10m 33s

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