fix typo

basis/Dockerfile

@@ -25,7 +25,7 @@ RUN apt-get update -y && apt-get upgrade -y && \
 
 ### installing pip packages
 RUN pip install numpy seaborn scipy matplotlib uncertainties pyunfold PhyPraKit pandas\
-    kafe2 pydot graphviz scikit-learn jupytext nbgitpuller jupyterlab-git ipympl pyarrow ipywidget --upgrade --no-cache-dir
+    kafe2 pydot graphviz scikit-learn jupytext nbgitpuller jupyterlab-git ipympl pyarrow ipywidgets --upgrade --no-cache-dir
 
 RUN pip install iminuit --no-cache