Bump tar and npm in /apps/ReverseProxy

Removes [tar](https://github.com/npm/node-tar). It's no longer used after updating ancestor dependency [npm](https://github.com/npm/cli). These dependencies need to be updated together.


Removes `tar`

Updates `npm` from 6.14.8 to 6.14.17
- [Release notes](https://github.com/npm/cli/releases)
- [Changelog](https://github.com/npm/cli/blob/v6.14.17/CHANGELOG.md)
- [Commits](npm/cli@v6.14.8...v6.14.17)

---
updated-dependencies:
- dependency-name: tar
  dependency-type: indirect
- dependency-name: npm
  dependency-type: direct:production
...

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

Author: dependabot[bot]

apps/ReverseProxy/package-lock.json

@@ -11,6 +11,6 @@
   "dependencies": {
     "cheerio": "^1.0.0-rc.3",
     "i": "^0.3.6",
-    "npm": "^6.14.8"
+    "npm": "^6.14.17"
   }
 }