Bump eslint from 2.13.1 to 4.18.2

Bumps [eslint](https://github.com/eslint/eslint) from 2.13.1 to 4.18.2.
- [Release notes](https://github.com/eslint/eslint/releases)
- [Changelog](https://github.com/eslint/eslint/blob/master/CHANGELOG.md)
- [Commits](https://github.com/eslint/eslint/compare/v2.13.1...v4.18.2)

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

packages/ripple-binary-codec/package.json

@@ -28,7 +28,7 @@
     "babel-preset-es2015": "^6.6.0",
     "babel-register": "^6.8.0",
     "codecov.io": "^0.1.6",
-    "eslint": "^2.9.0",
+    "eslint": "^4.18.2",
     "fs-extra": "^0.30.0",
     "intercept-stdout": "^0.1.2",
     "istanbul": "~0.4.3",