Update git submodules

* Update docs/submodules/fuel from branch 'master'
  - [repos] Replace keyserver accesses with pillar GPG

    JIRA: FUEL-392

    Change-Id: Ia21840c7561a14a5eeed3d08bf89eb2dbf9acc3a
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index 5693a22..d7bf560 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit 5693a22613d2ba0bd454490646c8a29b47a74329
+Subproject commit d7bf560e12151853c3121ba39ad9bf6bd47befcf