Fix issue when passing multiple `CMake` args

[JacobDomagala]

Using something like following doesn't work:

        cmake_args: >
          -D CMAKE_BUILD_TYPE="DEBUG"
          -D Trilinos_ENABLE_ALL_PACKAGES=ON
          -D Trilinos_ENABLE_ALL_OPTIONAL_PACKAGES=ON
          -D Trilinos_ALLOW_NO_PACKAGES=ON
          -D Trilinos_DISABLE_ENABLED_FORWARD_DEP_PACKAGES=ON
          -D Trilinos_IGNORE_MISSING_EXTRA_REPOSITORIES=ON
          -D Trilinos_ENABLE_TESTS=ON
          -D Trilinos_TEST_CATEGORIES=BASIC
          -D Trilinos_ENABLE_ALL_FORWARD_DEP_PACKAGES=ON
          -D Trilinos_VERBOSE_CONFIGURE=OFF
          -D BUILD_SHARED_LIBS:BOOL=ON
          -D Trilinos_WARNINGS_AS_ERRORS_FLAGS="-Wno-error"
          -D Trilinos_ENABLE_SEACAS=OFF
          -D Trilinos_ENABLE_Sacado=OFF
          -D TPL_ENABLE_BLAS=ON
          -D TPL_ENABLE_LAPACK=ON
          -D TPL_ENABLE_CUDA=OFF
          -D TPL_ENABLE_Matio=OFF
          -D TPL_ENABLE_X11=OFF
          -D TPL_ENABLE_Pthread=OFF
          -D TPL_ENABLE_Boost=OFF
          -D TPL_ENABLE_BoostLib=OFF
          -D TPL_ENABLE_ParMETIS=OFF
          -D TPL_ENABLE_Zlib=OFF
          -D TPL_ENABLE_HDF5=OFF
          -D TPL_ENABLE_Netcdf=OFF
          -D TPL_ENABLE_SuperLU=OFF
          -D TPL_ENABLE_Scotch=OFF
          -D TPL_ENABLE_MPI=ON
          -D Trilinos_ENABLE_Rythmos=OFF
          -D Trilinos_ENABLE_Pike=OFF
          -D Trilinos_ENABLE_Komplex=OFF
          -D Trilinos_ENABLE_TriKota=OFF
          -D Trilinos_ENABLE_Moertel=OFF
          -D Trilinos_ENABLE_Domi=OFF
          -D Trilinos_ENABLE_FEI=OFF
          -D Trilinos_ENABLE_PyTrilinos=OFF
          -D Trilinos_ENABLE_Epetra=OFF

We need to evaluate the cmake_args input