fix(package): update keyv to version 4.0.1

Closes #31

Author: greenkeeper[bot]

package.json

@@ -31,7 +31,7 @@
   },
   "dependencies": {
     "@keyv/redis": "^1.3.8",
-    "keyv": "^3.0.0"
+    "keyv": "^4.0.1"
   },
   "devDependencies": {
     "@babel/cli": "^7.1.2",