Relax EmPy version requirement now that v4 is working #558

Job	Run time
bootstrap / setup	2s
pytest / setup	2s
pytest / pytest (macos-latest, 3.8)	50s
pytest / pytest (macos-latest, 3.9)	41s
pytest / pytest (macos-latest, 3.10)	37s
pytest / pytest (macos-latest, 3.11)	40s
pytest / pytest (macos-latest, 3.12)	39s
pytest / pytest (ubuntu-latest, 3.8)	51s
pytest / pytest (ubuntu-latest, 3.9)	49s
pytest / pytest (ubuntu-latest, 3.10)	54s
pytest / pytest (ubuntu-latest, 3.11)	48s
pytest / pytest (ubuntu-latest, 3.12)	54s
pytest / pytest (windows-latest, 3.8)	46s
pytest / pytest (windows-latest, 3.9)	46s
pytest / pytest (windows-latest, 3.10)	44s
pytest / pytest (windows-latest, 3.11)	45s
pytest / pytest (windows-latest, 3.12)	49s
pytest / pytest (ubuntu-20.04, 3.6)	47s
bootstrap / bootstrap (macos-latest, 3.8)	1s
bootstrap / bootstrap (macos-latest, 3.9)	1s
bootstrap / bootstrap (macos-latest, 3.10)	1s
bootstrap / bootstrap (macos-latest, 3.11)	1s
bootstrap / bootstrap (macos-latest, 3.12)	1s
bootstrap / bootstrap (ubuntu-latest, 3.8)	1s
bootstrap / bootstrap (ubuntu-latest, 3.9)	1s
bootstrap / bootstrap (ubuntu-latest, 3.10)	20s
bootstrap / bootstrap (ubuntu-latest, 3.11)	18s
bootstrap / bootstrap (ubuntu-latest, 3.12)	22s
bootstrap / bootstrap (windows-latest, 3.8)	1s
bootstrap / bootstrap (windows-latest, 3.9)	1s
bootstrap / bootstrap (windows-latest, 3.10)	1s
bootstrap / bootstrap (windows-latest, 3.11)	1s
bootstrap / bootstrap (windows-latest, 3.12)	1s
bootstrap / bootstrap (ubuntu-20.04, 3.6)	25s
	14m 1s

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