Update git submodules

* Update docs/submodules/fuel from branch 'stable/euphrates'
  - pharos git submodule: Bump for latest PDF adapter

    Change-Id: I658c1dfeb369adf74038abd0ce1b593d40303527
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>
    (cherry picked from commit 5ad2e311bbc1326493386aeee4d87a9091337adf)

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index fb0a361..84fd2fa 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit fb0a36154d6354348078b6a0972655b0bfc60af4
+Subproject commit 84fd2fa61325bdc7c680f4f37c776313ca228530