Update to docker_based_installation.rst (#686)

Issue #685

Changed link to docker site to updated link.

I am new to github, this is the first time I am editing a file directly on the github website, not 100% sure if this will create a pull request the same way, so apologies if this is not what is required.

Co-authored-by: ReimarBauer <rb.proj@gmail.com>

docs/docker_based_installation.rst

@@ -1,7 +1,7 @@
 Installation based on Docker
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-Since 1.7.4 mss is on the `docker hub <https://hub.docker.com/r/dreimark/mss/>`_.
+Since 1.7.4 mss is on the `docker hub <https://hub.docker.com/orgs/openmss/>`_.
 
 Build settings are based on the stable branch. Our latest is any update in the stable repo.