Add forgotten \ :-"

Dockerfile

@@ -493,7 +493,7 @@ RUN pip install flashtext && \
  pip install albumentations && \
  pip install pytorch-ignite && \
  pip install qgrid && \
- pip install bqplot &&
+ pip install bqplot && \
  /tmp/clean-layer.sh
 
 # Tesseract and some associated utility packages