feat(docker): Add opencontainers image-spec to `Dockerfile`

[SauravMaheshkar]

Description

This PR makes a few tiny changes to improve the overall quality of the docker image 🐳 . For reference more annotations can be found here

Change log

• Add annotations to the Dockerfile

[mikemhenry]

@SauravMaheshkar Thanks for this! I am working on improving our Dockerfiles, so this is a great addition! :tada: