refactor: prepare the plugin for eslint's new 'flat-config'

following https://eslint.org/docs/latest/extend/plugin-migration-flat-config

lib/index.js

@@ -3,25 +3,43 @@
  * @author sverweij
  */
 
-module.exports = {
+// eslint-disable-next-line budapestian/global-constant-pattern
+const { name, version } = require("../package.json");
+
+const plugin = {
+  meta: {
+    name,
+    version,
+  },
   rules: {
     "parameter-pattern": require("./rules/parameter-pattern-rule"),
     "global-constant-pattern": require("./rules/global-constant-pattern-rule"),
     "global-variable-pattern": require("./rules/global-variable-pattern-rule"),
     "local-variable-pattern": require("./rules/local-variable-pattern-rule"),
   },
-  configs: {
-    recommended: {
-      plugins: ["budapestian"],
-      rules: {
-        "budapestian/parameter-pattern": "error",
-        "budapestian/global-variable-pattern": "error",
-        "budapestian/local-variable-pattern": [
-          "error",
-          { exceptions: ["i", "j", "k", "x", "y", "z"] },
-        ],
-        "budapestian/global-constant-pattern": "error",
-      },
+  configs: {},
+};
+
+// see https://eslint.org/docs/latest/extend/plugin-migration-flat-config why
+// configs is not defined directly in the plugin object
+Object.assign(plugin.configs, {
+  recommended: {
+    plugins: ["budapestian"],
+    // the above documentation recommends to use plugins: { budapestian: plugin }
+    // however, eslint 8 does not like that:
+    // ESLint: 8.52.0
+    //
+    // TypeError: Converting circular structure to JSON
+    rules: {
+      "budapestian/parameter-pattern": "error",
+      "budapestian/global-variable-pattern": "error",
+      "budapestian/local-variable-pattern": [
+        "error",
+        { exceptions: ["i", "j", "k", "x", "y", "z"] },
+      ],
+      "budapestian/global-constant-pattern": "error",
     },
   },
-};
+});
+
+module.exports = plugin;