proxy dockerfile #3634

Job	Run time
multiple-arch-aarch64	22m 8s
cygwin64-cache	1m 40s
utest-regression-blackbox-test	10m 2s
multiple-arch-armv7	22m 4s
cygwin64	15m 7s
fast	1s
build-cross-arm	5m 9s
build-ubuntu16	3m 4s
build-centos7	4m 51s
build-cross-aarch64	4m 59s
build-ubuntu18	2m 59s
build-ubuntu20	3m 43s
coverage	3m 33s
multiple-arch-amd64	2m 22s
test-done	1s
	1h 41m 43s

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