update google benchmark version

Author: ktrz

examples/cpp/Makefile

@@ -16,7 +16,7 @@ benchmark/build: benchmark
 	mkdir -p benchmark/build
 
 benchmark:
-	[ -d benchmark ] || git clone --depth=1 --single-branch --branch v1.5.0 https://github.com/google/benchmark.git benchmark
+	[ -d benchmark ] || git clone --depth=1 --single-branch --branch v1.9.3 https://github.com/google/benchmark.git benchmark
 
 benchmark/googletest: benchmark
 	[ -d benchmark/googletest ] || git clone --depth=1 --single-branch --branch release-1.12.1 https://github.com/google/googletest.git benchmark/googletest