Update eslintrc.json to accept ecmaVersion 2019/10 (#696)
Update eslintrc.json to accept ecmaVersion 2019/10 (#696)

Per [documentation](https://eslint.org/docs/user-guide/configuring):
> Set to 3, 5 (default), 6, 7, 8, 9, or 10 to specify the version of ECMAScript syntax you want to use. You can also set to 2015 (same as 6), 2016 (same as 7), 2017 (same as 8), 2018 (same as 9), or 2019 (same as 10) to use the year-based naming.
schemastore/schemastore,schemastore/schemastore