Use std::map.contains as per latest c++

This commit replaces occurrences of 'find' with
'contains' to access elements in a std::map
according to the latest C++ standard (since C++20).

However, contains() is not suitable in all situations
as in the case where we want to use the element contained
in the map using contains(), then it would do 2 searches
instead of 1 in the case where we use find() which fetches
the element from the map also.

Here are some relevant links to C++ documentation and
resources:

[1]: https://en.cppreference.com/w/cpp/container/map/find
[2]: https://en.cppreference.com/w/cpp/container/map/contains
[3]: https://wg21.link/N4861

Signed-off-by: Sagar Srinivas <sagar.srinivas@ibm.com>
Change-Id: If589e52026417c1c14a6a946e48826b749034e9a
diff --git a/libpldmresponder/fru.cpp b/libpldmresponder/fru.cpp
index de6fe1f..632489c 100644
--- a/libpldmresponder/fru.cpp
+++ b/libpldmresponder/fru.cpp
@@ -172,7 +172,7 @@
         const auto& interfaces = object.second;
         for (const auto& interface : interfaces)
         {
-            if (itemIntfsLookup.find(interface.first) != itemIntfsLookup.end())
+            if (itemIntfsLookup.contains(interface.first))
             {
                 // checking fru present property is available or not.
                 if (!pldm::utils::checkForFruPresence(object.first.str))