Fix Jackson deprecation warnings in MessagePackFactory

Replace deprecated _createContext(Object, boolean) calls with
_createContext(ContentReference, boolean) to eliminate warnings
when running tests with Jackson 2.18.4.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: xerial

msgpack-jackson/src/main/java/org/msgpack/jackson/dataformat/MessagePackFactory.java

@@ -19,6 +19,7 @@
 import com.fasterxml.jackson.core.JsonFactory;
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.io.ContentReference;
 import com.fasterxml.jackson.core.io.IOContext;
 import org.msgpack.core.MessagePack;
 import org.msgpack.core.annotations.VisibleForTesting;
@@ -111,15 +112,15 @@ public JsonGenerator createGenerator(Writer w)
     public JsonParser createParser(byte[] data)
             throws IOException
     {
-        IOContext ioContext = _createContext(data, false);
+        IOContext ioContext = _createContext(ContentReference.rawReference(data), false);
         return _createParser(data, 0, data.length, ioContext);
     }
 
     @Override
     public JsonParser createParser(InputStream in)
             throws IOException
     {
-        IOContext ioContext = _createContext(in, false);
+        IOContext ioContext = _createContext(ContentReference.rawReference(in), false);
         return _createParser(in, ioContext);
     }