chore: move to Traefik organization.

Co-authored-by: Romain <rtribotte@users.noreply.github.com>

docs/content/providers/docker.md

@@ -168,7 +168,7 @@ You can specify which Docker API Endpoint to use with the directive [`endpoint`]
         - [Don't expose the Docker socket (not even to a container)](https://www.lvh.io/posts/dont-expose-the-docker-socket-not-even-to-a-container/)
         - [A thread on Stack Overflow about sharing the `/var/run/docker.sock` file](https://news.ycombinator.com/item?id=17983623)
         - [To DinD or not to DinD](https://blog.loof.fr/2018/01/to-dind-or-not-do-dind.html)
-        - [Traefik issue GH-4174 about security with Docker socket](https://github.com/containous/traefik/issues/4174)
+        - [Traefik issue GH-4174 about security with Docker socket](https://github.com/traefik/traefik/issues/4174)
         - [Inspecting Docker Activity with Socat](https://developers.redhat.com/blog/2015/02/25/inspecting-docker-activity-with-socat/)
         - [Letting Traefik run on Worker Nodes](https://blog.mikesir87.io/2018/07/letting-traefik-run-on-worker-nodes/)
         - [Docker Socket Proxy from Tecnativa](https://github.com/Tecnativa/docker-socket-proxy)

docs/content/providers/kubernetes-ingress.md

@@ -391,4 +391,4 @@ providers:
 ### Further
 
 If one wants to know more about the various aspects of the Ingress spec that Traefik supports,
-many examples of Ingresses definitions are located in the tests [data](https://github.com/containous/traefik/tree/v2.3/pkg/provider/kubernetes/ingress/fixtures) of the Traefik repository.
+many examples of Ingresses definitions are located in the tests [data](https://github.com/traefik/traefik/tree/v2.3/pkg/provider/kubernetes/ingress/fixtures) of the Traefik repository.

docs/content/providers/marathon.md

@@ -32,7 +32,7 @@ See also [Marathon user guide](../user-guides/marathon.md).
 		"container": {
 			"type": "DOCKER",
 			"docker": {
-				"image": "containous/whoami",
+				"image": "traefik/whoami",
 				"network": "BRIDGE",
 				"portMappings": [
 					{