fix: update traefik middleware apiVersion (#704)

Author: holysoles

crowdsec-docs/unversioned/getting_started/installation/kubernetes.mdx

@@ -129,7 +129,7 @@ Traefik expects a resource of "Middleware" type named "bouncer", which we will c
 Here is bouncer-middleware.yaml:
   
 ```yaml
-apiVersion: traefik.containo.us/v1alpha1
+apiVersion: traefik.io/v1alpha1
 kind: Middleware
 metadata:
   name: bouncer