Update git submodules

* Update docs/submodules/fuel from branch 'master'
  - Revert "[salt-formulas] Switch to 'testing' dist"

    This reverts commit a8f434118013a69295bdc0f9fc8294c539742c01.
    This reverts commit b52ef6ea62f43de4b91e2becd92a3282e569925c.

    Change-Id: I604df3f50febb049f1545a8141c5abb013cf6c69
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index 1e76bad..5d54a99 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit 1e76bad68ffc8f4235d11599fdf074b38ac76c7b
+Subproject commit 5d54a99cb71172e5ccb1bff94bdd98c3212bd769