Update git submodules

* Update docs/submodules/fuel from branch 'stable/fraser'
  - [doc] Add guest OS support matrix

    Update fuel documentation regarding the guest operating systems
    that we can boot in both in x86 and aarch64.

    Change-Id: Iea96fae880755d0a9cc8fa519362ff564f79e391
    Signed-off-by: Charalampos Kominos <Charalampos.Kominos@enea.com>
    (cherry picked from commit 1cdebf06e880d7ff75c7700b4e7253206eef1763)

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index 6e28bce..ed32f87 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit 6e28bcea8eca57d6befae2cd272a39564b0311e5
+Subproject commit ed32f87371d5a3917910e010315b1565fce9b17d