Add typing in credentials module #391

Job	Run time
Test on python 3.7 and ubuntu-latest	2m 13s
Test on python 3.7 and windows-latest	2m 26s
Test on python 3.7 and macos-latest	20s
Test on python 3.8 and ubuntu-latest	1m 52s
Test on python 3.8 and windows-latest	2m 32s
Test on python 3.8 and macos-latest	44s
Test on python 3.9 and ubuntu-latest	1m 56s
Test on python 3.9 and windows-latest	2m 25s
Test on python 3.9 and macos-latest	35s
Test on python 3.10 and ubuntu-latest	1m 50s
Test on python 3.10 and windows-latest	2m 18s
Test on python 3.10 and macos-latest	20s
Test on python 3.11 and ubuntu-latest	1m 32s
Test on python 3.11 and windows-latest	2m 5s
Test on python 3.11 and macos-latest	20s
Test on python 3.12 and ubuntu-latest	1m 39s
Test on python 3.12 and windows-latest	2m 4s
Test on python 3.12 and macos-latest	22s
	27m 33s

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