use new count instead of deprecated thread_safe

Author: HDembinski

benchmark/histogram_parallel_filling.cpp

@@ -5,7 +5,7 @@
 // or copy at http://www.boost.org/LICENSE_1_0.txt)
 
 #include <benchmark/benchmark.h>
-#include <boost/histogram/accumulators/thread_safe.hpp>
+#include <boost/histogram/accumulators/count.hpp>
 #include <boost/histogram/axis/regular.hpp>
 #include <boost/histogram/histogram.hpp>
 #include <boost/histogram/make_histogram.hpp>
@@ -29,7 +29,7 @@ using namespace boost::histogram;
 using namespace std::chrono_literals;
 
 using DS = dense_storage<unsigned>;
-using DSTS = dense_storage<accumulators::thread_safe<unsigned>>;
+using DSTS = dense_storage<accumulators::count<unsigned, true>>;
 
 static void NoThreads(benchmark::State& state) {
   std::default_random_engine gen(1);