chore(deps): bump redis from 2.8.0 to 3.1.1

Bumps [redis](https://github.com/NodeRedis/node-redis) from 2.8.0 to 3.1.1.
- [Release notes](https://github.com/NodeRedis/node-redis/releases)
- [Changelog](https://github.com/NodeRedis/node-redis/blob/master/CHANGELOG.md)
- [Commits](redis/node-redis@v.2.8.0...v3.1.1)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

package-lock.json

@@ -73,6 +73,6 @@
     "dependencies": {
         "bluebird": "^3.5.5",
         "raven": "^2.6",
-        "redis": "^2.8"
+        "redis": "^3.1"
     }
 }