Tests

Added OAuth v2 and files_upload_v2 samples. #1397

Job	Run time
test (ruby=2.7)	31s
test (ruby=2.7, concurrency=async-websocket)	33s
test (ruby=3.0)	19s
test (ruby=3.1)	20s
test (ruby=3.2)	25s
test (ruby=3.3)	23s
test (ruby=ruby-head)	21s
test (ruby=jruby-head)	2m 1s
coveralls	3s
	4m 56s

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