fix(package): update redis to version 2.8.0 (#4087)

Author: greenkeeper[bot]

package.json

@@ -35,7 +35,7 @@
     "parse-server-s3-adapter": "1.1.0",
     "parse-server-simple-mailgun-adapter": "1.0.0",
     "pg-promise": "6.3.1",
-    "redis": "2.7.1",
+    "redis": "2.8.0",
     "request": "2.81.0",
     "semver": "5.3.0",
     "tv4": "1.3.0",