Update dependency django-cors-headers to v4

requirements.txt

@@ -7,7 +7,7 @@
 backcall==0.2.0           # via ipython
 click==7.1.2                # via pip-tools
 decorator==4.4.2          # via ipython, traitlets
-django-cors-headers==2.5.3
+django-cors-headers==4.3.1
 django-extensions==2.2.9
 django-guardian==1.5.1
 django-webpack-loader==0.7.0