Tests

Rename `files_upload_external` to `files_upload_v2` #1369

Job	Run time
test (ruby=2.7)	31s
test (ruby=2.7, concurrency=async-websocket)	31s
test (ruby=3.0)	21s
test (ruby=3.1)	24s
test (ruby=3.2)	25s
test (ruby=3.3)	28s
test (ruby=ruby-head)	21s
test (ruby=jruby-head)	1m 57s
coveralls	5s
	5m 3s

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