message: Update material compat package README to add Button
diff: @@ -51,6 +51,7 @@ import { QueryBuilderMaterial } from '@react-querybuilder/material';
  import { QueryBuilder, RuleGroupType } from 'react-querybuilder';
  // MUI component imports
  import DragIndicator from '@mui/icons-material/DragIndicator';
  +import Button from '@mui/material/Button';
  import Checkbox from '@mui/material/Checkbox';
  import FormControl from '@mui/material/FormControl';
  import FormControlLabel from '@mui/material/FormControlLabel';
  @@ -65,6 +66,7 @@ import TextareaAutosize from '@mui/material/TextareaAutosize';
  // Assign the MUI components to an object
  const muiComponents = {
  + Button,
  Checkbox,
  DragIndicator,
  FormControl,
  