refactor(pdf_extract_kit): update model config and weight paths for UniMERNet-0.2.0

Update the paths to model weights and configuration files for the UniMERNet architecture
in both the demo.yaml and model_configs.yaml files. Adjust the mfr_model_init function toreflect the new weight and configuration paths. The changes include specifying more detailed
paths to the unimernet_base directory and changing the weight file extension to .pth.

requirements-docker.txt

@@ -8,7 +8,7 @@ fast-langdetect==0.2.0
 wordninja>=2.0.0
 scikit-learn>=1.0.2
 pdfminer.six==20231228
-unimernet==0.1.6
+unimernet==0.2.0
 matplotlib
 ultralytics
 paddleocr==2.7.3