Update git submodules

* Update docs/submodules/fuel from branch 'stable/euphrates'
  - [baremetal] Add upstream (lab) proxy support

    If upstream proxy is defined in IDF, propagate it to pillar data:
    - linux:system:proxy:keyserver:http(s) for cfg01, mas01;
    - maas:region:upstream_proxy for mas01;

    Sample IDF config:

    idf:
      fuel:
        network:
          upstream_proxy:
            address: 10.0.2.2
            port: 3128

    JIRA: FUEL-317

    Change-Id: I12be815e1b4564227fb09c20ce06cd71e7d433b6
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index ba3d752..0c7d890 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit ba3d7527637414175f5a142fa92cd9ea5d2e3158
+Subproject commit 0c7d890cdb20fdcf2a5e0e0a629088ee045cf4af