Update repository urls on projects file example

Updates the old grimoirelab repositories used as an example of a projects.json file on /sirmordred/projects.md
to reflect that are now under chaoss organization

Signed-off-by: Eva Millán <[email protected]>

Author: evamillan

sirmordred/projects.md

@@ -56,15 +56,15 @@ As an example, this is an excerpt of the projects file for the CHAOSS dashboard:
 {
     "GrimoireLab": {
         "git": [
-            "https://github.com/grimoirelab/arthur",
-            "https://github.com/grimoirelab/grimoireelk",
-            "https://github.com/grimoirelab/mordred",
+            "https://github.com/chaoss/grimoirelab-kingarthur",
+            "https://github.com/chaoss/grimoirelab-elk",
+            "https://github.com/chaoss/grimoirelab-sirmordred",
             ...
         ],
         "github": [
-            "https://github.com/grimoirelab/arthur",
-            "https://github.com/grimoirelab/grimoireelk",
-            "https://github.com/grimoirelab/mordred",
+            "https://github.com/chaoss/grimoirelab-kingarthur",
+            "https://github.com/chaoss/grimoirelab-elk",
+            "https://github.com/chaoss/grimoirelab/mordred",
             ...
         ],
         "pipermail": [