Fix eslint errors after bump to 6.6.0 (#1595)

* Bump eslint from 3.19.0 to 6.6.0

Bumps [eslint](https://github.com/eslint/eslint) from 3.19.0 to 6.6.0.
- [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/v3.19.0...v6.6.0)

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

* Fix (and suppress) eslint errors

package.json

@@ -12,7 +12,7 @@
     "addons-linter": "^1.3.2",
     "ajv": "^6.6.2",
     "chai": "^4.1.2",
-    "eslint": "^3.17.1",
+    "eslint": "^6.6.0",
     "eslint-plugin-no-unsanitized": "^2.0.0",
     "eslint-plugin-promise": "^3.4.0",
     "htmllint-cli": "0.0.7",