chore: use JS config file (mysticatea#18)

Author: MichaelDeBoey

.eslintrc.js

@@ -0,0 +1,22 @@
+"use strict"
+
+/** @type {import('eslint').Linter.Config} */
+module.exports = {
+    root: true,
+    extends: ["plugin:@eslint-community/mysticatea/es2020"],
+    rules: {
+        "@eslint-community/mysticatea/prettier": "off",
+    },
+    overrides: [
+        {
+            files: ["src/**/*.js", "test/**/*.js"],
+            extends: ["plugin:@eslint-community/mysticatea/+modules"],
+            rules: {
+                "init-declarations": "off",
+
+                "@eslint-community/mysticatea/node/no-unsupported-features/es-syntax":
+                    ["error", { ignores: ["modules"] }],
+            },
+        },
+    ],
+}