Add changelog for 0.40.0-rc4

CHANGELOG.md

+## 0.40.0-rc4 (2024-11-05)
+
+### Added (3 changes)
+
+- [Support `warning_on_none_empty_plan` input in pipeline templates](https://gitlab.com/components/opentofu/-/commit/27a482a76e7ee35b94f8539a50ecdf325f8711cb) ([merge request](https://gitlab.com/components/opentofu/-/merge_requests/170))
+- [Support `warning_on_none_empty_plan` input in `plan` job.](https://gitlab.com/components/opentofu/-/commit/4065954e5f9cefe02dc526951efb28afc7e8b661) ([merge request](https://gitlab.com/components/opentofu/-/merge_requests/170))
+- [Pass `plan` input down from compound templates](https://gitlab.com/components/opentofu/-/commit/4005bfaa98b82c73fbadaff6428398f9a0af15d6) ([merge request](https://gitlab.com/components/opentofu/-/merge_requests/169))
+
+### Removed (1 change)
+
+- [Remove old OpenTofu versions](https://gitlab.com/components/opentofu/-/commit/0a106f377cf0cafaeaed7db71d9b2761a9ca33d2) ([merge request](https://gitlab.com/components/opentofu/-/merge_requests/171))
+
+### Development (1 change)
+
+- [This is a changelog test commit](https://gitlab.com/components/opentofu/-/commit/7cba70e7b82843b05bf4c5bfcb2e7260596e4d04)
+
 ## 0.40.0-rc3 (2024-11-05)
 
 ### Added (1 change)