clang-tidy: Enable readability-convert-member-functions-to-static

This check finds non-static member functions that can be made
static because the functions don’t use this.
This check also triggers readability-static-accessed-through
-instance check as we are trying to access a static member
function through an instance.

Change-Id: Ia0867db019db8e40e710bdd4025e030061f7a992
Signed-off-by: Pavithra Barithaya <pavithrabarithaya07@gmail.com>
diff --git a/sync_manager.hpp b/sync_manager.hpp
index 98e7b95..82fe266 100644
--- a/sync_manager.hpp
+++ b/sync_manager.hpp
@@ -32,7 +32,7 @@
      * @param[in] entryPath - The file or directory to process.
      * @param[out] result - 0 if successful.
      */
-    int processEntry(int mask, const fs::path& entryPath);
+    static int processEntry(int mask, const fs::path& entryPath);
 };
 
 } // namespace manager