Switch doc and source versions to iron

Signed-off-by: Yadunund <[email protected]>

Author: Yadunund

iron/distribution.yaml

@@ -4395,7 +4395,7 @@ repositories:
     doc:
       type: git
       url: https://github.com/open-rmf/rmf_visualization.git
-      version: main
+      version: iron
     release:
       packages:
       - rmf_visualization
@@ -4413,7 +4413,7 @@ repositories:
     source:
       type: git
       url: https://github.com/open-rmf/rmf_visualization.git
-      version: main
+      version: iron
     status: developed
   rmf_visualization_msgs:
     doc: