Bump actions/download-artifact from 7 to 8 #3755

Job	Run time
Run release tests	21s
Run Guideline Recategorization tests	20s
Prepare supported CodeQL environment matrix	4s
Run analysis report tests (2.21.4, codeql-cli/v2.21.4, codeql-bundle-v2.21.4)	4m 48s
	5m 33s

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