Fix types in QuestionGroupChart component

src/App.tsx

@@ -35,7 +35,7 @@ function App() {
 
   // Create scales
   const xScale = d3
-    .scaleBand()
+    .scaleBand<number>()
     .domain(sortedResponses)
     .range([0, sortedResponses.length * config.groupSpacing]);
   return (

src/components/QuestionGroupChart.tsx

@@ -10,9 +10,9 @@ import "./Chart.css";
 interface QuestionGroupChartProps {
   question: string;
   metadata?: CategoryMetadata;
-  groupData: { response: string }[];
-  responses: string[];
-  xScale: d3.ScaleBand<string>;
+  groupData: { response: number }[];
+  responses: number[];
+  xScale: d3.ScaleBand<number>;
 }
 
 function makeDot(