Update git submodules

* Update docs/submodules/snaps from branch 'master'
  - Refactoring of VolumeTypeSettings to extend VolumeTypeConfig

    This also includes VolumeTypeEncryptionSettings extending to
    VolumeTypeEncryptionConfig which is a member of VolumeTypeConfig
    VolumeTypeSettings and cinder_utils have a runtime cyclical
    dependency. This patch reduces this dependency and
    deprecates the VolumeTypeSettings class.

    JIRA: SNAPS-228

    Change-Id: Iaa9c7a1cd810cf63d1badb00f71bcdcefb527e12
    Signed-off-by: spisarski <s.pisarski@cablelabs.com>

diff --git a/docs/submodules/snaps b/docs/submodules/snaps
index 6dd10aa..3c387ae 160000 (submodule)
--- a/docs/submodules/snaps
+++ b/docs/submodules/snaps
@@ -1 +1 @@
-Subproject commit 6dd10aa17c12bac0c3c185b15a444a5437563c14
+Subproject commit 3c387ae1c18c4a80a752c3e5a2409f4a602b9e20