Leave project-vision-doc-2025 team

I joined the project-vision-doc-2025 team explicitly in the capacity
of keeping context on the PM-related activities of the Project, as
these activities are a focus of certain council priorities on which
I've been leading the charge.

With the team spun up and operating actively, and having now brought
Tomas on board the Project (and with the recent decision that his
efforts won't at this time be needed as part of the vision doc work),
I don't need to be on the team any longer, and so it's time for me to
leave it in its many capable hands.

Author: traviscross

teams/project-vision-doc-2025.toml

@@ -13,11 +13,11 @@ members = [
     "joshtriplett",
     "workingjubilee",
     "timClicks",
-    "traviscross",
     "PLeVasseur",
 ]
 alumni = [
     "spastorino",
+    "traviscross",
 ]
 
 [[github]]