Include Material for MkDocs 6.0 in trivadis/mktools docker image

[PhilippSalvisberg]

Material for MkDocs 6.0 has just been released.

Provide a docker image with tags 2.1 and latest with this new version.

[PhilippSalvisberg]

No change in the Dockerfile necessary.
Just a new docker image and a rebuild of the PDF and HTML site.

[PhilippSalvisberg]

New Docker image is available under https://hub.docker.com/repository/docker/trivadis/mktools/tags
Main branch deployed on https://trivadis.github.io/plsql-and-sql-coding-guidelines/main/