Add '+upstream' suffix to published deb version #69

Job	Run time
pytest / setup	2s
pytest / pytest (macos-latest, 3.8)	1m 20s
pytest / pytest (macos-latest, 3.9)	1m 7s
pytest / pytest (macos-latest, 3.10)	1m 0s
pytest / pytest (macos-latest, 3.11)	50s
pytest / pytest (macos-latest, 3.12)	41s
pytest / pytest (ubuntu-22.04, 3.8)	1m 31s
pytest / pytest (ubuntu-22.04, 3.9)	1m 32s
pytest / pytest (ubuntu-22.04, 3.10)	1m 36s
pytest / pytest (ubuntu-22.04, 3.11)	3m 7s
pytest / pytest (ubuntu-22.04, 3.12)	4m 12s
pytest / pytest (windows-latest, 3.8)	3m 9s
pytest / pytest (windows-latest, 3.9)	3m 12s
pytest / pytest (windows-latest, 3.10)	2m 40s
pytest / pytest (windows-latest, 3.11)	2m 43s
pytest / pytest (windows-latest, 3.12)	2m 37s
pytest / pytest (ubuntu-20.04, 3.6)	51s
	32m 10s

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