Removed unnecessary explicit ecmaVersion lint rule

refs 42ddda5

- With a bump of the eslint-plugin-ghost to 2.14.0 it's no longer needed to explicitly specify the preferred ecmaVersion as it's been set as a default

Author: naz

packages/admin-api-schema/.eslintrc.js

@@ -1,7 +1,4 @@
 module.exports = {
-    parserOptions: {
-        ecmaVersion: 2020
-    },
     plugins: ['ghost'],
     extends: [
         'plugin:ghost/node'