Remove WEBrick from OpenURI tests #130

Job	Run time
ruby-versions / Generate Ruby versions	3s
build (2.5 / ubuntu-latest)	40s
build (2.5 / windows-latest)	2m 2s
build (2.6 / ubuntu-latest)	50s
build (2.6 / macos-latest)	1m 12s
build (2.6 / windows-latest)	6h 0m 5s
build (2.7 / ubuntu-latest)	49s
build (2.7 / macos-latest)	1m 7s
build (2.7 / windows-latest)	5h 59m 40s
build (3.0 / ubuntu-latest)	36s
build (3.0 / macos-latest)	51s
build (3.0 / windows-latest)	5h 59m 30s
build (3.1 / ubuntu-latest)	38s
build (3.1 / macos-latest)	53s
build (3.1 / windows-latest)	5h 59m 27s
build (3.2 / ubuntu-latest)	36s
build (3.2 / macos-latest)	58s
build (3.2 / windows-latest)	5h 59m 21s
build (3.3 / ubuntu-latest)	31s
build (3.3 / macos-latest)	46s
build (3.3 / windows-latest)	5h 59m 19s
build (head / ubuntu-latest)	37s
build (head / macos-latest)	51s
build (head / windows-latest)	5h 59m 16s
	1d 18h 10m 38s

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