Point agent component at its gh-pages branch, not master

Documentation for component repos lives on a dedicated branch
(reusing the existing gh-pages branch convention, modernized) rather
than on master, keeping docs fully separated from application code.

Author: gm2552

scripts/components.json

@@ -2,6 +2,6 @@
   {
     "slug": "agent",
     "repo": "https://github.com/DirectProjectJavaRI/agent.git",
-    "branch": "master"
+    "branch": "gh-pages"
   }
 ]