Tests/FindBoost/TestPython: support finding 3.8 and 3.9

Tests/FindBoost/TestPython/CMakeLists.txt

@@ -2,10 +2,10 @@ cmake_minimum_required(VERSION 3.14)
 project(TestFindBoostPython CXX)
 include(CTest)
 
-find_package(Boost OPTIONAL_COMPONENTS python27 python34 python35 python36 python37)
+find_package(Boost OPTIONAL_COMPONENTS python27 python34 python35 python36 python37 python38 python39)
 
 set(FAILTEST TRUE)
-foreach (v IN ITEMS 27 34 35 36 37)
+foreach (v IN ITEMS 27 34 35 36 37 38 39)
   if (Boost_PYTHON${v}_FOUND)
     set(FAILTEST FALSE)
     break()