Add all_files to support multiple file uploads in names ending with [] #400

Job	Run time
ameba (ubuntu-latest, latest)	1m 7s
test (ubuntu-latest, latest)	2m 33s
format (ubuntu-latest, latest)	11s
test (ubuntu-latest, nightly)	1m 47s
format (ubuntu-latest, nightly)	16s
test (macos-latest, latest)	2m 17s
test (macos-latest, nightly)	1m 49s
test (windows-latest, latest)	2m 25s
test (windows-latest, nightly)	2m 53s
	15m 18s

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