Update mev-boost and mev-boost-relay for fusaka-devnet-3 (#277)

Signed-off-by: Bharath Vedartham <vedabharath12345@gmail.com>

Author: bharath-123

branches.yaml

@@ -183,14 +183,14 @@ mev-boost:
     - develop
   alt_repos:
     bharath-123/mev-boost:
-      - bharath/fulu
+      - fusaka-devnet-3
 
 mev-boost-relay:
   branches:
     - main
   alt_repos:
     bharath-123/mev-boost-relay:
-      - bharath/fulu
+      - fusaka-devnet-3
 ethrex:
   branches:
     - main