Bump eslint from 6.8.0 to 7.18.0 (#413)

Bumps [eslint](https://github.com/eslint/eslint) from 6.8.0 to 7.18.0.
- [Release notes](https://github.com/eslint/eslint/releases)
- [Changelog](https://github.com/eslint/eslint/blob/master/CHANGELOG.md)
- [Commits](eslint/eslint@v6.8.0...v7.18.0)

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

package.json

@@ -22,7 +22,7 @@
     "chakram": "^1.5.0",
     "cheerio": "^1.0.0-rc.5",
     "csv-parse": "^4.14.2",
-    "eslint": "6.8.0",
+    "eslint": "7.18.0",
     "mimelib": "^0.3.1",
     "mocha": "^8.2.1",
     "mqtt": "^3.0.0",