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/manager.cpp b/manager.cpp
index 6f286df..fe0f605 100644
--- a/manager.cpp
+++ b/manager.cpp
@@ -26,8 +26,7 @@
     }
     else
     {
-        auto search = assertedGroups.find(&ledMap.at(path));
-        if (search != assertedGroups.end())
+        if (assertedGroups.contains(&ledMap.at(path)))
         {
             assertedGroups.erase(&ledMap.at(path));
         }