clang-format: update to latest from docs repo

The openbmc/docs/style/cpp/.clang-format has been updated to support
clang-format10, take this opportunity to update it in this repo.

Change-Id: I9e6b9853bf4cd7399b1ae504ea3be5093d763fee
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/download_manager.cpp b/download_manager.cpp
index a3811dd..06f4c78 100644
--- a/download_manager.cpp
+++ b/download_manager.cpp
@@ -7,12 +7,13 @@
 #include <sys/wait.h>
 #include <unistd.h>
 
-#include <algorithm>
-#include <filesystem>
-#include <iostream>
 #include <phosphor-logging/elog-errors.hpp>
 #include <phosphor-logging/elog.hpp>
 #include <phosphor-logging/log.hpp>
+
+#include <algorithm>
+#include <filesystem>
+#include <iostream>
 #include <string>
 
 namespace phosphor