update eslint

Author: zloirock

.eslintrc.js

@@ -62,6 +62,8 @@ const base = {
   'no-unexpected-multiline': 'error',
   // disallow negation of the left operand of an in expression
   'no-unsafe-negation': 'error',
+  // disallow use of optional chaining in contexts where the `undefined` value is not allowed
+  'no-unsafe-optional-chaining': 'error',
   // disallow loops with a body that allows only one iteration
   'no-unreachable-loop': 'error',
   // disallow useless backreferences in regular expressions

package.json

@@ -26,7 +26,7 @@
     "babel-plugin-transform-for-of-as-array": "^1.1.1",
     "david": "^12.0.0",
     "es-observable": "git+https://github.com/tc39/proposal-observable.git#d3404f06bc70c7c578a5047dfb3dc813730e3319",
-    "eslint": "^7.14.0",
+    "eslint": "^7.15.0",
     "eslint-import-resolver-webpack": "~0.13.0",
     "eslint-plugin-import": "^2.22.1",
     "eslint-plugin-node": "^11.1.0",