fix syntax error

Author: basnijholt

docs/environment.yml

@@ -5,14 +5,14 @@ channels:
 
 dependencies:
   - python
-  - sortedcollections=2.2.2
+  - sortedcollections=1.2.1
   - scikit-optimize=0.8.1
   - scikit-learn=0.23.2
   - scipy=1.5.2
   - holoviews=1.13.3
-  - bokeh=2.2.1=
+  - bokeh=2.2.1
   - plotly=4.10.0
-  - ipywidget7.5.1
+  - ipywidgets=7.5.1
   - jupyter_sphinx=0.3.1
   - atomicwrites=1.4.0
   - sphinx_fontawesome=0.0.6