Add some mirrors for mtools. #118

Job	Run time
update-cache-and-deploy / set-variables	3s
update-cache-and-deploy / update-cvd-test-bazel-cache	14m 27s
update-cache-and-deploy / update-bazel-cache-and-deploy-debian-package-arm64	17m 48s
update-cache-and-deploy / update-bazel-cache-and-deploy-debian-package-amd64	19m 17s
update-cache-and-deploy / deploy-docker-image-arm64	2m 8s
update-cache-and-deploy / deploy-docker-image-amd64	1m 56s
update-cache-and-deploy / deploy-docker-manifest	12s
	55m 51s

Provide feedback