Update version string to 1.6.1rc2 (#1437)

Author: yunchu

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## May 2024 Release 1.6.1
 ### Bug fixes
+- Relax Pillow dependency constraint
+  (<https://github.com/openvinotoolkit/datumaro/pull/1436>)
 - Modify Numpy dependency constraint
   (<https://github.com/openvinotoolkit/datumaro/pull/1435>)
 

src/datumaro/version.py

@@ -1 +1 @@
-__version__ = "1.6.1rc1"
+__version__ = "1.6.1rc2"