Fix typing for PBES and PKCS8 #824

Job	Run time
mypy	16s
build_python_27 (ubuntu-20.04, yes)	2m 18s
build_python_27 (ubuntu-20.04, no)	2m 14s
test_c_linux (0, x64)	50s
build_python_27 (windows-latest, yes)	3m 24s
test_c_windows (x64)	1m 3s
test_c_linux (0, x32)	58s
build (3.5, yes, ubuntu-20.04)	2m 18s
build_python_27 (windows-latest, no)	3m 22s
test_c_windows (win32)	39s
build (3.5, no, ubuntu-20.04)	2m 11s
test_c_linux (1, x64)	1m 20s
build (3.6, yes, ubuntu-20.04)	2m 16s
test_c_linux (1, x32)	1m 19s
build (3.6, no, ubuntu-20.04)	2m 15s
build (3.7, yes, ubuntu-20.04)	2m 6s
build (3.7, no, ubuntu-20.04)	2m 11s
build (3.8, yes, ubuntu-20.04)	1m 59s
build (3.8, no, ubuntu-20.04)	2m 8s
build (3.9, yes, ubuntu-20.04)	2m 17s
build (3.9, no, ubuntu-20.04)	2m 5s
build (3.10, yes, ubuntu-20.04)	1m 58s
build (3.10, no, ubuntu-20.04)	2m 2s
build (3.11, yes, ubuntu-20.04)	1m 47s
build (3.11, no, ubuntu-20.04)	1m 46s
build (3.12-dev, yes, ubuntu-20.04)	1m 50s
build (3.12-dev, no, ubuntu-20.04)	1m 55s
build (3.11, yes, macos-12)	5m 38s
build (3.11, no, windows-latest)	3m 44s
build (3.11, yes, windows-latest)	4m 26s
build (3.12-dev, no, windows-latest)	3m 45s
build (3.12-dev, yes, windows-latest)	4m 26s
build (pypy2.7, no, ubuntu-latest)	1m 26s
build (pypy3.9, no, ubuntu-latest)	1m 38s
	1h 15m 50s

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