Update git submodules

* Update docs/submodules/fuel from branch 'master'
  - [patch] maas: rebase artifact download

    Upstream refactored maas/regions.sls to introduce kitchen tests in
    [1], rebase our patches on top of it.

    [1] https://github.com/salt-formulas/salt-formula-maas/commit/8a0d52e

    Change-Id: I491fb2e05679ebc226a27141e685d429e0ff8bcc
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index 016db55..e2c554c 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit 016db55bd5cc07d32926b60d59b1fdd7e2471705
+Subproject commit e2c554c856a923c4a6323c96a190fd82e3d049d7