Dockerfile: fix links in same step as generating the files
Dockerfile: fix links in same step as generating the files

For intermediate stages, it's generally ok to perform steps
separately, however in this case, fixing the links would
happen every time the HTML was generated, so we might as
well do it in the same step, to reduce the size of the local
build cache, as it was adding 54MB for each rebuild:

    IMAGE               CREATED             CREATED BY                                      SIZE                COMMENT
    7d97d86ae290        3 minutes ago       RUN /bin/sh -c find ${TARGET} -type f -name …   53.7MB              buildkit.dockerfile.v0
    <missing>           3 minutes ago       RUN /bin/sh -c jekyll build -d ${TARGET} # b…   375MB               buildkit.dockerfile.v0

Signed-off-by: Sebastiaan van Stijn <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@gone.nl>

thaJeztah/docker.github.io,docker/docker.github.io,docker/docker.github.io,docker/docker.github.io,thaJeztah/docker.github.io,thaJeztah/docker.github.io,thaJeztah/docker.github.io,docker/docker.github.io,docker/docker.github.io,thaJeztah/docker.github.io