[ui][widgets] Fix render signature

Support for Widget.render() methods without
the renderer argument is removed.


See:

https://docs.djangoproject.com/en/2.1/releases/2.1/#features-removed-in-2-1

beat/web/ui/widgets.py

@@ -312,7 +312,7 @@ class CodeMirrorTextarea(forms.Textarea):
 
         self.config = config or {}
 
-    def render(self, name, value, attrs=None):
+    def render(self, name, value, attrs=None, renderer=None):
         """Render CodeMirrorTextarea"""
 
         if self.size is not None:
@@ -328,7 +328,7 @@ class CodeMirrorTextarea(forms.Textarea):
         )
 
         output = [
-            super(CodeMirrorTextarea, self).render(name, value, attrs),
+            super().render(name, value, attrs, renderer),
             '<script type="text/javascript">var %(name)s_editor = CodeMirror.fromTextArea(document.getElementById("id_%(name)s"), %(options)s);%(suffix)s</script>'
             % dict(name=name, options=option_json, suffix=suffix,),
         ]
@@ -341,13 +341,11 @@ class CodeMirrorFileWidget(CodeMirrorTextarea):
     def __init__(self, *args, **kwargs):
         super(CodeMirrorFileWidget, self).__init__(*args, **kwargs)
 
-    def render(self, name, value, attrs=None):
+    def render(self, name, value, attrs=None, renderer=None):
         if isinstance(value, str):
             contents = value
         elif hasattr(value, "read"):
             contents = value.read()
         else:
             contents = ""
-        return mark_safe(  # nosec
-            super(CodeMirrorFileWidget, self).render(name, contents, attrs)
-        )
+        return mark_safe(super().render(name, contents, attrs, renderer))  # nosec