Update git submodules

* Update docs/submodules/snaps from branch 'master'
  - Added substitution variable support.

    Change-Id: I57e10be315c288d75d61b014940cd02c0c0134fa
    Signed-off-by: spisarski <s.pisarski@cablelabs.com>

diff --git a/docs/submodules/snaps b/docs/submodules/snaps
index 345cc4e..58ae4e5 160000 (submodule)
--- a/docs/submodules/snaps
+++ b/docs/submodules/snaps
@@ -1 +1 @@
-Subproject commit 345cc4e80de42729f62bd2c5cfe6a2e31273ac4d
+Subproject commit 58ae4e51e160ee243e2761e5bdaf42508d6097dc