Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "refactor the part to get credential file"
  - refactor the part to get credential file

    Change-Id: Iebab0714f1cd7123c18d98a41b7da224726c5421
    Signed-off-by: xudan <xudan16@huawei.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 9f2107e..2875f7d 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 9f2107eb7569697a77f74cec6894637318e0fac7
+Subproject commit 2875f7d7903099dd6c0e8e85502d0a2f0cba1496