Update git submodules

Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - New PTL for Dovetail

    This patch is used as a basis for voting on the new Dovetail PTL.  After
    the nomination period [1] has ended, there is one candidate [2].

    In order to complete the PTL election process, all Dovetail committers
    shall review this patch and cast a vote (-1, +1). The voting period ends
    in a week from now on October 24. The vote passes if a majority of
    committers +1 this patch.

    [1] https://lists.opnfv.org/g/opnfv-tech-discuss/message/22133
    [2] https://lists.opnfv.org/g/opnfv-tech-discuss/message/22145

    Change-Id: Iacf53f5c0bbe7e0c5f3c47131569be72ed8623ec
    Signed-off-by: Georg Kunz <georg.kunz@ericsson.com>