CHANGELOG.md in benchmark_driver-0.14.6 vs CHANGELOG.md in benchmark_driver-0.14.7

@@ -1,4 +1,9 @@
+# v0.14.7
+
+- Fix bug on warmup with `BenchmarkDriver::BulkOutput` [#40](https://github.com/benchmark-driver/benchmark-driver/issues/40)
+  - This is currently used by benchmark\_driver-output-gruff
+
 # v0.14.6
 
 - Improve option parser validation
 - Add `--timeout` option only for Linux having timeout(1)
 - Support `--version` option