Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "updated auto.yaml with 6.1.0 commit"
  - updated auto.yaml with 6.1.0 commit

    master commit to use for 6.1.0:
    b718a43380376d2b19222c4203c97a95ca849ae8

    (note: opnfv-6.1.0 tag: 553ea71b7aa2eb7d9ff46316de367dff0844ce42)
    (can/should a tag objet ID be used for a point release ?)

    updated stable/fraser SHA1, to same SHA1 that was used for 6.0.0
    (i.e. 3a957a75f99686767d13f45d74b5ca8463559b7b)

    (I assume stable/fraser SHA1 should be the same as 6.0.0 SHA1 ?)
    >The stable ref is the ref when the branch was created, it should not
    >change
    (cherry-picking for stable/fraser is not possible after 6.0.0 is
    released)
    >You can cherry pick as long as you want.

    Change-Id: I887174801a56b374cae0197b31561673bc0435ea
    Signed-off-by: Gerard Damm <gerard.damm@wipro.com>