proxy dockerfile #3630

Job	Run time
multiple-arch-armv7	22m 6s
cygwin64-cache	2m 7s
utest-regression-blackbox-test	9m 44s
multiple-arch-aarch64	22m 56s
fast	1s
cygwin64	14m 44s
build-ubuntu18	3m 6s
build-cross-aarch64	5m 21s
build-centos7	4m 52s
build-cross-arm	5m 37s
build-ubuntu16	3m 11s
build-ubuntu20	3m 33s
coverage	3m 24s
multiple-arch-amd64	2m 20s
test-done	0s
	1h 43m 2s

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