chore(deps): update dependency django-tinymce to v4

Author: renovate[bot]

requirements/base.txt

@@ -43,7 +43,7 @@ django-autocomplete-light==3.11.0
 # django-ajax-datatable==4.4.5
 git+https://github.com/PiotrIw/django-ajax-datatable.git@05afe42
 
-django-tinymce==3.7.1
+django-tinymce==4.1.0
 
 # replacing unmaintained django-atom with updated fork
 # django-atom==0.16.3