Update CMakeLists.txt (#109)

Make cmake look for BehaviorTreeV3 rather than BehaviorTree, fixes #108

Author: MoritzWillmann

CMakeLists.txt

@@ -81,7 +81,7 @@ set(CATKIN_ENABLE_TESTING OFF CACHE BOOL "")
 
 if(NOT catkin_FOUND AND NOT ament_cmake_FOUND)
     # look for BehaviorTree.CPP on the system
-    find_package(BehaviorTree)
+    find_package(BehaviorTreeV3)
     if (NOT BehaviorTree_FOUND)
         # use git submodule only if you are not compiling with catkin
         add_subdirectory( depend/BehaviorTree.CPP )