chore(package): update eslint to version 6.7.0

Closes #35

Author: greenkeeper[bot]

package.json

@@ -33,7 +33,7 @@
 	"devDependencies": {
 		"owe-core": "0.11.x",
 		"owe.js": "0.11.x",
-		"eslint": "4.19.1",
+		"eslint": "6.7.0",
 		"eslint-config-cortys": "1.x",
 		"chai": "4.1.2",
 		"chai-as-promised": "7.1.1",