Update requirements.txt

Author: yunchu

src/otx/api/usecases/exportable_code/demo/requirements.txt

@@ -1,4 +1,4 @@
 openvino==2023.0
 openvino-model-api==0.1.2
-otx @ git+https://github.com/openvinotoolkit/training_extensions/@77b635f4fba0a8acca221ec7e8b1fadd734358da#egg=otx
+otx==1.4.0rc1
 numpy>=1.21.0,<=1.23.5  # np.bool was removed in 1.24.0 which was used in openvino runtime