Add DockerHub notary signing to all official images e.g. adoptopenjdk/openjdk11

[rhuddleston]

$ export DOCKER_CONTENT_TRUST=1
$ docker pull adoptopenjdk/openjdk11:alpine-jre
Error: remote trust data does not exist for docker.io/adoptopenjdk/openjdk11: notary.docker.io does not have trust data for docker.io/adoptopenjdk/openjdk11

$ docker pull adoptopenjdk/openjdk11:latest
Error: remote trust data does not exist for docker.io/adoptopenjdk/openjdk11: notary.docker.io does not have trust data for docker.io/adoptopenjdk/openjdk11

$ docker pull adoptopenjdk/openjdk11:jre-11.0.3_7
Error: remote trust data does not exist for docker.io/adoptopenjdk/openjdk11: notary.docker.io does not have trust data for docker.io/adoptopenjdk/openjdk11

it would be nice if theses images could be signed.

[grzesuav]

notaryproject/notary#1370

[grzesuav]

quoting:

When you run docker build, it tries to verify the image you are building from using the content trust server you specified. There is no trust data for the official ubuntu library in your content trust server. You would have to either sign the image yourself on your local notary server or override the DOCKER_CONTENT_TRUST_SERVER to be https://notary.docker.io for the docker build command specifically.