Update git submodules

* Update docs/submodules/snaps from branch 'master'
  - Create download directory if not exists before downloading image file.

    Change-Id: I6d51681d4e0d58b96a00bfeb144d6bfcb8ae04e6
    Signed-off-by: spisarski <s.pisarski@cablelabs.com>

diff --git a/docs/submodules/snaps b/docs/submodules/snaps
index 0f407db..8f681f8 160000 (submodule)
--- a/docs/submodules/snaps
+++ b/docs/submodules/snaps
@@ -1 +1 @@
-Subproject commit 0f407db1cc01d8d58e4e0b0f4ecafc69ef1a17a4
+Subproject commit 8f681f8dcf0526e2db3d648234f89bf03bcc23df