Update app-template submodule.

Update app-template submodule.

Updating project configuration file following the app-template
submodule update which let the command-line argument override
the project configuration.

Submodule conf.d/app-templates 76e12e7..0f25ab2:
  > Adding warning message to migrate on CMake module
  > common.cmake: fixed erroneous search path for os-release
  > Fix: missing gcov symbol in compiled binaries

Bugs-AGL: SPEC-1798

Change-Id: I614f2fc6e2ff9b95a62e5a3113930b9181bbcd2a
Signed-off-by: Romain Forlot <romain.forlot@iot.bzh>