fix: type Grid size proptype to accep grow and auto values (mui#323)

Author: ablagoev

packages/pigment-css-react/src/Grid.jsx

@@ -300,6 +300,7 @@ process.env.NODE_ENV !== 'production' &&
      */
     size: PropTypes /* @typescript-to-proptypes-ignore */.oneOfType([
       PropTypes.arrayOf(PropTypes.number),
+      PropTypes.oneOf(['grow', 'auto']),
       PropTypes.number,
       PropTypes.object,
     ]),

packages/pigment-css-react/tests/Grid/fixtures/Grid.output.js

@@ -394,6 +394,7 @@ process.env.NODE_ENV !== 'production' &&
      */
     size: PropTypes /* @typescript-to-proptypes-ignore */.oneOfType([
       PropTypes.arrayOf(PropTypes.number),
+      PropTypes.oneOf(['grow', 'auto']),
       PropTypes.number,
       PropTypes.object,
     ]),