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/phosphor-regulators/test/test_sdbus_error.hpp b/phosphor-regulators/test/test_sdbus_error.hpp
index 09cc5f7..1937e2d 100644
--- a/phosphor-regulators/test/test_sdbus_error.hpp
+++ b/phosphor-regulators/test/test_sdbus_error.hpp
@@ -29,8 +29,7 @@
 {
   public:
     TestSDBusError(const std::string& error) : error{error}
-    {
-    }
+    {}
 
     const char* what() const noexcept override
     {