Update git submodules

Update git submodules

* Update docs/submodules/clamp.git from branch 'master'
  to 6d8bb93e25f82d8eea0c5211bd630804866f3097
  - Merge "Improve unit tests and sonar fixes"
  - Improve unit tests and sonar fixes

    Add more test to CryptoUtilsTest and JsonUtilsTest.
    Correct sonar issue in CldsServiceItCase test - checking if stream is not null.
    Remove unused import in CldsHealthcheckServiceItCase.
    Remove unused field in DocumentBuilderTest.
    Add private constructor in PrincipalUtils and XmlTools.
    Add FEATURE_SECURE_PROCESSING feature to TransformerFactory.

    Change-Id: Ieeb561352697c131ebf11bc43162f63ea7096e81
    Issue-ID: CLAMP-355
    Signed-off-by: Krystian Kedron <k.kedron@partner.samsung.com>