added image labels org.opencontainers.image.{title,source,revision}

https://github.com/fphammerle/docker-onion-service-status-mail/commit/fb929bc5e6aeea8d84c5842a9375f86e48be6fc9
https://github.com/fphammerle/docker-onion-service/commit/aa124bde955047b2de6316ff72d6b1f76d14e3ba
https://github.com/fphammerle/docker-onion-service/commit/46ca6d70fb2d4570bfddac6b3f5e485183e72405

CHANGELOG.md

@@ -6,8 +6,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 ### Added
-- `openssh-server`: added `ed25519` host key
-- `docker-compose`: added cpu & memory resource limits
+- `openssh-server`: `ed25519` host key
+- `docker-compose`: cpu & memory resource limits
+- image labels:
+  - `org.opencontainers.image.revision` (git commit hash via build arg)
+  - `org.opencontainers.image.source` (repo url)
+  - `org.opencontainers.image.title`
 
 ### Changed
 - authorize public keys in env var `SSH_CLIENT_PUBLIC_KEYS`

Dockerfile

@@ -25,3 +25,9 @@ ENTRYPOINT ["/sbin/tini", "--", "/entrypoint.sh"]
 
 USER $USER
 CMD ["/usr/sbin/sshd", "-D", "-e"]
+
+# https://github.com/opencontainers/image-spec/blob/v1.0.1/annotations.md
+ARG REVISION=
+LABEL org.opencontainers.image.title="single-user openssh server executing mysqldump when client connects" \
+    org.opencontainers.image.source="https://github.com/fphammerle/docker-mysqldump-sshd" \
+    org.opencontainers.image.revision="$REVISION"