Update dependency eslint-config-airbnb-base to v15

Author: renovate[bot]

package.json

@@ -52,7 +52,7 @@
     "chai": "4.2.0",
     "coveralls": "3.1.0",
     "eslint": "7.11.0",
-    "eslint-config-airbnb-base": "14.2.0",
+    "eslint-config-airbnb-base": "15.0.0",
     "eslint-config-prettier": "6.14.0",
     "eslint-plugin-import": "2.22.1",
     "eslint-plugin-prettier": "3.1.4",