Update git submodules

Update git submodules

* Update docs/submodules/sdc.git from branch 'master'
  to 28f3de6c698075c2282493309722c8c29e95b523
  - ZipSlip test fails on Mac OS

    Mac OS has a symlink in the tmp dir that gets created in the test for
    ZipSlip.  Using real paths prevents the test test from failing by using
    actual paths instead of a potentially different symlinked path to the
    canonical path.

    Issue-ID: SDC-2887
    Signed-off-by: neil.derraugh <neil.derraugh@yoppworks.com>
    Change-Id: Iafb0a84f6ab68276c5782c1ef716c59435aa72f5