Redis Add image source label to dockerfiles

To get changelogs shown with Renovate a docker container has to add the source label described in the OCI Image Format Specification.

For reference: https://github.com/renovatebot/renovate/blob/main/lib/modules/datasource/docker/readme.md

LABEL org.opencontainers.image.source="https://github.com/renovatebot/renovate"

Comment From: sundb

@wuast94 i can't follow you, we don't have dockerfile in Redis repo.

Comment From: wuast94

i couldnt find where its build and pushed to dockerhub so i asked here.

Comment From: sundb

should be https://github.com/redis/docker-library-redis