Replace find method with contains method

- The intent behind of this commit is to replace the `find` method
  with the `contains` method.

- `contains` is a new feature of C++20, it will check if there is an
  element with key equivalent to key in the container and return
  true or false.

Tested: built ledManager repo successfully and CI passed.

Signed-off-by: George Liu <liuxiwei@inspur.com>
Change-Id: I09121154983defe051c48e6470a976c5b229a2e7
diff --git a/json-config.hpp b/json-config.hpp
index d3a59a1..b9bb36f 100644
--- a/json-config.hpp
+++ b/json-config.hpp
@@ -104,7 +104,7 @@
 
         msg.read(path, interfaces);
 
-        if (interfaces.find(confCompatibleInterface) == interfaces.end())
+        if (!interfaces.contains(confCompatibleInterface))
         {
             return;
         }
@@ -113,7 +113,7 @@
         // "xyz.openbmc_project.Configuration.IBMCompatibleSystem" interface
         const auto& properties = interfaces.at(confCompatibleInterface);
 
-        if (properties.find(confCompatibleProperty) == properties.end())
+        if (!properties.contains(confCompatibleProperty))
         {
             return;
         }