Tests

tests: Ensure `dbapi2.Error` sets `cause` #906

Job	Run time
Build bloomberg-comdb2 from source	4m 21s
Build python-comdb2 source distribution	23s
Test suite (3.13)	41s
Test suite (3.10)	27s
Test suite (3.11)	53s
Test suite (3.12)	41s
Test suite (3.9)	42s
Test suite (3.8)	36s
	8m 44s

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