clang updates

The openbmc CI was recently updated to clang-12 which requires some
formatting updates to the code:
https://github.com/openbmc/openbmc-build-scripts/commit/4569bf49daaebff06be0482426908bb5497fad08

Make those updates and refresh the clang-format file with the one from
docs:
https://github.com/openbmc/docs/blob/master/style/cpp/.clang-format

Change-Id: Ieb3626526373a053ec84431e7560003f229f338d
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/device_monitor.hpp b/device_monitor.hpp
index 7960d1c..ec0151c 100644
--- a/device_monitor.hpp
+++ b/device_monitor.hpp
@@ -43,8 +43,7 @@
                   std::chrono::milliseconds i) :
         device(std::move(d)),
         timer(e, std::bind(&DeviceMonitor::analyze, this), i)
-    {
-    }
+    {}
 
     /**
      * Starts the timer to monitor the device on an interval.