clang-tidy: Enable modernize-use-nullptr check

This check converts the usage of null pointer constants
(e.g. NULL, 0) to use the new C++11 and C23 nullptr keyword.

Change-Id: I8b1dc27f62e8825538d8f276c0f99375a1a5d158
Signed-off-by: Pavithra Barithaya <pavithrabarithaya07@gmail.com>
diff --git a/.clang-tidy b/.clang-tidy
index c382910..ff2531a 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -221,6 +221,7 @@
 modernize-use-equals-default,
 modernize-use-equals-delete,
 modernize-use-noexcept,
+modernize-use-nullptr,
 modernize-use-override,
 modernize-use-transparent-functors,
 modernize-use-uncaught-exceptions,