bump cmake_minimum_required to 2.8.8

Author: Taiju Yamada

CMakeLists.txt

@@ -11,7 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-cmake_minimum_required (VERSION 2.8.0)
+cmake_minimum_required (VERSION 2.8.8)
 project(mujincontrollerclient)
 set( CMAKE_ALLOW_LOOSE_LOOP_CONSTRUCTS TRUE )