chore(xo-server-usage-report): use Babel 7

packages/xo-server-usage-report/.babelrc.js

@@ -0,0 +1,3 @@
+module.exports = require('../../@xen-orchestra/babel-config')(
+  require('./package.json')
+)

packages/xo-server-usage-report/package.json

@@ -35,18 +35,16 @@
   },
   "dependencies": {
     "@xen-orchestra/cron": "^1.0.3",
-    "babel-runtime": "^6.23.0",
     "handlebars": "^4.0.6",
     "html-minifier": "^3.5.8",
     "lodash": "^4.17.4",
     "promise-toolbox": "^0.9.5"
   },
   "devDependencies": {
-    "babel-cli": "^6.24.1",
+    "@babel/cli": "7.0.0-rc.1",
+    "@babel/core": "7.0.0-rc.1",
+    "@babel/preset-env": "7.0.0-rc.1",
     "babel-plugin-lodash": "^3.3.2",
-    "babel-plugin-transform-runtime": "^6.23.0",
-    "babel-preset-env": "^1.5.2",
-    "babel-preset-stage-3": "^6.24.1",
     "cross-env": "^5.1.3",
     "rimraf": "^2.6.1"
   },
@@ -57,22 +55,5 @@
     "prebuild": "yarn run clean",
     "predev": "yarn run prebuild",
     "prepublishOnly": "yarn run build"
-  },
-  "babel": {
-    "plugins": [
-      "lodash",
-      "transform-runtime"
-    ],
-    "presets": [
-      [
-        "env",
-        {
-          "targets": {
-            "node": 4
-          }
-        }
-      ],
-      "stage-3"
-    ]
   }
 }