Upgrade `upload-artifact` and `download-artifact` actions to v4 #68

Job	Run time
Pre-commit checks / Pre-commit Checks	18s
Build apps (3.10, ppb) / Verify App Build	2m 17s
Build apps (3.10, toga) / Verify App Build	2m 9s
Build apps (3.10, pygame) / Verify App Build	2m 1s
Build apps (3.10, pyside6) / Verify App Build	3m 28s
Build apps (3.11, ppb) / Verify App Build	2m 1s
Build apps (3.11, pyside6) / Verify App Build	4m 6s
Build apps (3.11, pygame) / Verify App Build	2m 23s
Build apps (3.11, toga) / Verify App Build	1m 41s
Build apps (3.12, ppb) / Verify App Build	2m 39s
Build apps (3.12, pygame) / Verify App Build	2m 14s
Build apps (3.12, pyside6) / Verify App Build	3m 25s
Build apps (3.12, toga) / Verify App Build	2m 16s
Build apps (3.8, ppb) / Verify App Build	2m 22s
Build apps (3.8, pygame) / Verify App Build	2m 8s
Build apps (3.8, pyside6) / Verify App Build	4m 2s
Build apps (3.8, toga) / Verify App Build	2m 52s
Build apps (3.9, ppb) / Verify App Build	2m 4s
Build apps (3.9, pygame) / Verify App Build	2m 6s
Build apps (3.9, pyside6) / Verify App Build	3m 33s
Build apps (3.9, toga) / Verify App Build	2m 7s
	52m 12s

Provide feedback