Update git submodules

* Update docs/submodules/armband from branch 'stable/danube'
  - docs: Update release date

    Change-Id: I659946aef133af3b99120903d57527daccf67f53
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>
    (cherry picked from commit be00c803bcefb56ad9f690ae1509d3dcae7e9d9b)

diff --git a/docs/submodules/armband b/docs/submodules/armband
index 2720a12..f6a2018 160000 (submodule)
--- a/docs/submodules/armband
+++ b/docs/submodules/armband
@@ -1 +1 @@
-Subproject commit 2720a12fea8f0b3296f50a9b0bc8816876586d9d
+Subproject commit f6a2018ff391d7b9f4f3aa0a3a364bfd9c3e7547