Make contribution graph email grouping ignore case

This makes the contribution graph grouping by contributor emails
case-insensitive

Changelog: fixed

app/assets/javascripts/contributors/stores/getters.js

@@ -7,10 +7,11 @@ export const parsedData = (state) => {
   state.chartData.forEach(({ date, author_name, author_email }) => {
     total[date] = total[date] ? total[date] + 1 : 1;
 
-    const authorData = byAuthorEmail[author_email];
+    const normalizedEmail = author_email.toLowerCase();
+    const authorData = byAuthorEmail[normalizedEmail];
 
     if (!authorData) {
-      byAuthorEmail[author_email] = {
+      byAuthorEmail[normalizedEmail] = {
         name: author_name,
         commits: 1,
         dates: {

spec/frontend/contributors/store/getters_spec.js

@@ -35,7 +35,7 @@ describe('Contributors Store Getters', () => {
           { author_name: 'Carlson', author_email: 'carlson123@gmail.com', date: '2019-05-05' },
           { author_name: 'John', author_email: 'jawnnypoo@gmail.com', date: '2019-04-04' },
           { author_name: 'Johan', author_email: 'jawnnypoo@gmail.com', date: '2019-04-04' },
-          { author_name: 'John', author_email: 'jawnnypoo@gmail.com', date: '2019-03-03' },
+          { author_name: 'John', author_email: 'JAWNNYPOO@gmail.com', date: '2019-03-03' },
         ];
         parsed = getters.parsedData(state);
       });