Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Apex: Refactor snapshot pipeline for other types"
  - Apex: Refactor snapshot pipeline for other types

    This patch changes snapshot related scripts to allow for more than just
    the current snapshot type of "csit". This allows us to add other
    snapshot types, including the functest type. The same
    snapshot.properties file will be used to store information for all types
    of snapshots. The snap cache folder structure will remain the same, but
    hold different types of snapshots in the same folders.

    These changes include renaming the URLs for the snapshot artifacts to
    reflect the snapshot type, but remains backwards compatible until enough
    promotions have occurred and other apex snapshot deployment scripts have
    been migrated to the new format.

    Change-Id: If3e47e700b5ad9c95418179042b85814fe389233
    Signed-off-by: Tim Rozet <trozet@redhat.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 465dcef..3970f5f 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 465dcefcd136847b8de27f83627dba3f76d72715
+Subproject commit 3970f5ffe03148df980f6e1518dcb105799a53d7