chore(deps-dev): bump eslint from 7.20.0 to 7.21.0

Bumps [eslint](/~https://github.com/eslint/eslint) from 7.20.0 to 7.21.0.
- [Release notes](/~https://github.com/eslint/eslint/releases)
- [Changelog](/~https://github.com/eslint/eslint/blob/master/CHANGELOG.md)
- [Commits](eslint/eslint@v7.20.0...v7.21.0)

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

package.json

@@ -52,7 +52,7 @@
     "@rollup/plugin-commonjs": "17.1.0",
     "@rollup/plugin-node-resolve": "11.2.0",
     "babel-plugin-add-module-exports": "1.0.4",
-    "eslint": "7.20.0",
+    "eslint": "7.21.0",
     "eslint-config-google": "0.14.0",
     "fancy-log": "1.3.3",
     "fs-extra": "9.1.0",