Use datetime instead of date

- Change merged_at_after
and merged_at_before to datetime

app/assets/javascripts/lib/utils/datetime_utility.js

@@ -561,3 +561,6 @@ export const getDateInPast = (date, daysInPast) => {
     dateClone.setTime(dateClone.getTime() - daysInPast * 24 * 60 * 60 * 1000),
   ).toISOString();
 };
+
+export const beginOfDayTime = 'T00:00:00Z';
+export const endOfDayTime = 'T23:59:59Z';

ee/app/assets/javascripts/analytics/productivity_analytics/store/modules/filters/getters.js

 import dateFormat from 'dateformat';
 import { urlParamsToObject } from '~/lib/utils/common_utils';
-import { getDateInPast } from '~/lib/utils/datetime_utility';
+import { getDateInPast, beginOfDayTime, endOfDayTime } from '~/lib/utils/datetime_utility';
 import { chartKeys, scatterPlotAddonQueryDays } from '../../../constants';
 import { dateFormats } from '../../../../shared/constants';
 
@@ -15,8 +15,8 @@ import { dateFormats } from '../../../../shared/constants';
  *   author_username: 'author',
  *   milestone_title: 'my milestone',
  *   label_name: ['my label', 'yet another label'],
- *   merged_at_after: '2019-06-11'
- *   merged_at_before: '2019-09-09'
+ *   merged_at_after: '2019-06-11T00:00:00Z'
+ *   merged_at_before: '2019-09-09T23:59:59Z'
  * }
  *
  */
@@ -39,8 +39,8 @@ export const getCommonFilterParams = state => chartKey => {
     author_username,
     milestone_title,
     label_name,
-    merged_at_after: mergedAtAfterDate,
-    merged_at_before: dateFormat(endDate, dateFormats.isoDate),
+    merged_at_after: `${mergedAtAfterDate}${beginOfDayTime}`,
+    merged_at_before: `${dateFormat(endDate, dateFormats.isoDate)}${endOfDayTime}`,
   };
 };
 

ee/spec/frontend/analytics/productivity_analytics/store/modules/filters/getters_spec.js

@@ -29,8 +29,8 @@ describe('Productivity analytics filter getters', () => {
           author_username: 'root',
           group_id: 'gitlab-org',
           label_name: ['labelxyz'],
-          merged_at_after: '2019-09-01',
-          merged_at_before: '2019-09-07',
+          merged_at_after: '2019-09-01T00:00:00Z',
+          merged_at_before: '2019-09-07T23:59:59Z',
           milestone_title: 'foo',
           project_id: 'gitlab-org/gitlab-test',
         };
@@ -47,8 +47,8 @@ describe('Productivity analytics filter getters', () => {
           author_username: 'root',
           group_id: 'gitlab-org',
           label_name: ['labelxyz'],
-          merged_at_after: '2019-08-02',
-          merged_at_before: '2019-09-07',
+          merged_at_after: '2019-08-02T00:00:00Z',
+          merged_at_before: '2019-09-07T23:59:59Z',
           milestone_title: 'foo',
           project_id: 'gitlab-org/gitlab-test',
         };