Stop using deprecated API: `Py_UNICODE` #524

Job	Run time
Build Wheels on macos-11-macosx_x86_64	14m 15s
Build Wheels on windows-2019-win32	8m 28s
Build Wheels on windows-2019-win_amd64	7m 15s
Source distribution	0s
Test wheels on macos-10.15-macosx_x86_64-3.7	1s
Test wheels on macos-10.15-macosx_x86_64-3.8	1s
Test wheels on macos-10.15-macosx_x86_64-3.9	1s
Test wheels on macos-10.15-macosx_x86_64-3.10	1s
Test wheels on macos-10.15-macosx_x86_64-3.11	1s
Test wheels on windows-2019-win32-3.7	56s
Test wheels on windows-2019-win32-3.8	1m 9s
Test wheels on windows-2019-win32-3.9	1m 3s
Test wheels on windows-2019-win32-3.10	1m 9s
Test wheels on windows-2019-win32-3.11	53s
Test wheels on windows-2019-win_amd64-3.7	40s
Test wheels on windows-2019-win_amd64-3.8	40s
Test wheels on windows-2019-win_amd64-3.9	1m 4s
Test wheels on windows-2019-win_amd64-3.10	55s
Test wheels on windows-2019-win_amd64-3.11	55s
Building and testing of wheels success	1s
Upload wheels	1s
	39m 29s

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