Update git submodules

* Update docs/submodules/sdc.git from branch 'master'
  to d426d3a68f0cd5313cc7d543f74af97580e59493
  - Work around potential NullPointerExceptions in ToscaElementLifecycleOperation

    - Rewrite of `checkinToscaELement`
    - Extracted methods from `checkinToscaELement`

    Issue-ID: SDC-2964
    Signed-off-by: Chris Andre <chris.andre@yoppworks.com>
    Change-Id: I99d2c5aaa73b955ef5aa60eeb7644bb47ac12bd6

diff --git a/docs/submodules/sdc.git b/docs/submodules/sdc.git
index 0a65c2f..d426d3a 160000 (submodule)
--- a/docs/submodules/sdc.git
+++ b/docs/submodules/sdc.git
@@ -1 +1 @@
-Subproject commit 0a65c2fe97240e892c8c65af2c9e6048aa350857
+Subproject commit d426d3a68f0cd5313cc7d543f74af97580e59493