Bump actions/download-artifact from 7 to 8 #3721

Job	Run time
Run Guideline Recategorization tests	17s
Prepare supported CodeQL environment matrix	6s
Run release tests	18s
Run analysis report tests (2.21.4, codeql-cli/v2.21.4, codeql-bundle-v2.21.4)	4m 43s
	5m 24s

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