avoid usage of to*Case + add project lint rule

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

plugins/xcmetrics/package.json

@@ -28,6 +28,7 @@
     "@material-ui/core": "^4.12.2",
     "@material-ui/icons": "^4.9.1",
     "@material-ui/lab": "4.0.0-alpha.57",
+    "lodash": "^4.17.21",
     "luxon": "^2.0.2",
     "react": "^16.13.1",
     "react-dom": "^16.13.1",

plugins/xcmetrics/src/utils/format.ts

@@ -15,6 +15,7 @@
  */
 import { DateTime, Duration } from 'luxon';
 import { BuildStatus } from '../api';
+import upperFirst from 'lodash/upperFirst';
 
 export const formatDuration = (seconds: number) => {
   const duration = Duration.fromObject({
@@ -48,5 +49,4 @@ export const formatPercentage = (number: number) => {
   return `${Math.round(number * 100)} %`;
 };
 
-export const formatStatus = (status: BuildStatus) =>
-  status[0].toUpperCase() + status.slice(1);
+export const formatStatus = (status: BuildStatus) => upperFirst(status);