[pkg-go] umoci is marked for autoremoval from testing

[Debian testing autoremoval watch]

umoci 0.4.4+dfsg-1 is marked for autoremoval from testing on 2019-03-11

It (build-)depends on packages with these RC bugs:
918618: golang-github-grpc-ecosystem-grpc-gateway: golang-github-grpc-ecosystem-grpc-gateway FTBFS: github.com/grpc-ecosystem/grpc-gateway/runtime [build failed]
920009: golang-google-cloud: golang-google-cloud FTBFS with golang-google-genproto-dev 0.0~git20190111.db91494-1
921156: etcd: CVE-2018-1098 CVE-2018-1099