ci(conformance): pin harness to 0.2.0-alpha.3 with expected-failures baseline #2703

Job	Run time
checks / readme-snippets	15s
checks / pre-commit	39s
checks / test (3.10, lowest-direct, windows-latest)	1m 36s
checks / test (3.10, lowest-direct, ubuntu-latest)	1m 3s
checks / test (3.14, lowest-direct, windows-latest)	1m 40s
checks / test (3.11, locked, ubuntu-latest)	59s
checks / test (3.10, locked, ubuntu-latest)	55s
checks / test (3.13, locked, ubuntu-latest)	51s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 25s
checks / test (3.11, lowest-direct, ubuntu-latest)	1m 4s
checks / test (3.11, lowest-direct, windows-latest)	1m 37s
checks / test (3.12, locked, ubuntu-latest)	57s
checks / test (3.11, locked, windows-latest)	1m 44s
checks / test (3.10, locked, windows-latest)	1m 32s
checks / test (3.13, lowest-direct, ubuntu-latest)	1m 1s
checks / test (3.12, locked, windows-latest)	1m 33s
checks / test (3.14, locked, windows-latest)	2m 7s
checks / test (3.13, locked, windows-latest)	1m 18s
checks / test (3.13, lowest-direct, windows-latest)	1m 34s
checks / test (3.14, lowest-direct, ubuntu-latest)	52s
checks / test (3.12, lowest-direct, windows-latest)	1m 48s
checks / test (3.14, locked, ubuntu-latest)	1m 59s
all-green	6s
	28m 35s

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