[eslint config] [base] [breaking] Set 'strict' to 'never'

Previously `rules/strict.js` was only used by `eslint-config-airbnb`
and not base. This change reduces the duplication, and means the rule
is now set to 'never' as opposed to the ESLint default of 'safe'.

For users that left the `sourceType` at this preset's default of
`module` this change will be a no-op, since in module-mode the
`strict` rule always behaves as though 'never' had been set.

See:
https://eslint.org/docs/rules/strict#options

Author: edmorley

packages/eslint-config-airbnb-base/index.js

@@ -7,12 +7,11 @@ module.exports = {
     './rules/variables',
     './rules/es6',
     './rules/imports',
+    './rules/strict',
   ].map(require.resolve),
   parserOptions: {
     ecmaVersion: 2018,
     sourceType: 'module',
   },
-  rules: {
-    strict: 'error',
-  },
+  rules: {},
 };