Bump angular from 1.5.7 to 1.8.3 in /zeppelin-web

Bumps [angular](https://github.com/angular/angular.js) from 1.5.7 to 1.8.3.
- [Changelog](https://github.com/angular/angular.js/blob/master/CHANGELOG.md)
- [Commits](angular/angular.js@v1.5.7...v1.8.3)

---
updated-dependencies:
- dependency-name: angular
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

zeppelin-web/package.json

@@ -26,7 +26,7 @@
   "dependencies": {
     "mathjax": "3.0.0",
     "ace-builds": "1.3.2",
-    "angular": "1.5.7",
+    "angular": "1.8.3",
     "angular-animate": "1.5.7",
     "angular-ui-bootstrap": "~2.5.0",
     "angular-cookies": "1.5.7",