Update git submodules

* Update docs/submodules/fuel from branch 'stable/fraser'
  - Merge "[xdf] Fix parsing of non-range private vlan(s)" into stable/fraser
  - [xdf] Fix parsing of non-range private vlan(s)

    Private (tenant) vlan range support introduced a regression in parsing
    PDF/IDF with a single vlan (no range) due to the value being
    interpreted as an int instead of string.

    Change-Id: Id5d67c4c516a9bb807ffa5e111ead5cbcee7e2ca
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>
    (cherry picked from commit 0bc600fd4d269a17ebcf28700b46e199d66c25db)

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index fb78f20..c8dcc5d 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit fb78f2057df57af51a257c4605ff28cbec97cc79
+Subproject commit c8dcc5d5dd821120dbe8320ab5adc805ff6ea5c2