bump common to have the new simplelog (#31)

Author: Barthelemy

CMakeLists.txt

@@ -57,7 +57,7 @@ endif()
 include(ExternalProject)
 externalproject_add (Common-standalone
   GIT_REPOSITORY "https://github.com/AliceO2Group/Common.git"
-  GIT_TAG "v1.2.5"
+  GIT_TAG "v1.4.7"
   LOG_DOWNLOAD 1
   UPDATE_COMMAND ""
   PATCH_COMMAND ""