Update git submodules

* Update docs/submodules/fuel from branch 'master'
  - Merge "docs: Add network layout example diagrams"
  - docs: Add network layout example diagrams

    JIRA: FUEL-295

    Change-Id: I3d7958951f1b37fe34dfaa28710a7f286a7a549a
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index 90f8b0e..b1ea72b 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit 90f8b0e41c000855ab2951fa9df1d913a67b3b2c
+Subproject commit b1ea72ba2c441a59327cc931b95bb7ece41591d0