Add typings #516

Job	Run time
test-postgres (9.5)	3m 3s
test-postgres (9.6)	2m 52s
test-platforms (3.8, ubuntu-latest, asyncio)	2m 10s
test-postgres (10)	3m 0s
test-platforms (3.8, ubuntu-latest, uvloop)	2m 9s
test-postgres (11)	2m 30s
test-postgres (12)	2m 24s
test-platforms (3.8, macos-latest, asyncio)	3m 28s
test-postgres (13)	2m 37s
test-platforms (3.8, macos-latest, uvloop)	3m 42s
test-postgres (14)	2m 13s
test-postgres (15)	2m 30s
test-platforms (3.8, windows-latest, asyncio)	5m 33s
test-platforms (3.9, ubuntu-latest, asyncio)	2m 0s
test-postgres (16)	2m 32s
test-platforms (3.9, ubuntu-latest, uvloop)	2m 2s
test-platforms (3.9, macos-latest, asyncio)	3m 24s
test-platforms (3.9, macos-latest, uvloop)	4m 18s
test-platforms (3.9, windows-latest, asyncio)	4m 57s
test-platforms (3.10, ubuntu-latest, asyncio)	1m 57s
test-platforms (3.10, ubuntu-latest, uvloop)	1m 59s
test-platforms (3.10, macos-latest, asyncio)	2m 46s
test-platforms (3.10, macos-latest, uvloop)	5m 40s
test-platforms (3.10, windows-latest, asyncio)	5m 19s
test-platforms (3.11, ubuntu-latest, asyncio)	1m 58s
test-platforms (3.11, ubuntu-latest, uvloop)	2m 1s
test-platforms (3.11, macos-latest, asyncio)	2m 52s
test-platforms (3.11, macos-latest, uvloop)	3m 33s
test-platforms (3.11, windows-latest, asyncio)	5m 21s
test-platforms (3.12, ubuntu-latest, asyncio)	1m 57s
test-platforms (3.12, macos-latest, asyncio)	3m 6s
test-platforms (3.12, windows-latest, asyncio)	6m 0s
Regression Tests	1s
	1h 41m 54s

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