Migrate ESLint config to v9

- Ran `npx @eslint/migrate-config .eslintrc.json` to migrate the config
- Ran `npm install globals @eslint/js @eslint/eslintrc -D` as instructed in the migration command output
- Changed `github/recommended` to their new flatConfigs
- Renamed `filenames/match-regex` to `github/filenames-match-regex` because the former is no longer maintained
- Renamed `import/no-namespace` to "importPlugin/no-namespace"
- Changed `eslint-disable no-console` to `eslint no-console: "off"` as the former no longer worked

Ref: https://eslint.org/docs/latest/use/migrate-to-9.0.0
Ref: https://eslint.org/docs/latest/use/configure/migration-guide
Ref: https://github.com/github/eslint-plugin-github?tab=readme-ov-file#flat-configuration-eslint-configjs

__tests__/main.test.ts

@@ -1,4 +1,4 @@
-/* eslint-disable no-console */
+/* eslint no-console: "off" */
 import * as child_process from 'child_process'
 import * as path from 'path'
 import * as process from 'process'

eslint.config.mjs

@@ -0,0 +1,81 @@
+import typescriptEslint from "@typescript-eslint/eslint-plugin";
+import stylistic from "@stylistic/eslint-plugin";
+import antiTrojanSource from "eslint-plugin-anti-trojan-source";
+import jest from "eslint-plugin-jest";
+import globals from "globals";
+import tsParser from "@typescript-eslint/parser";
+import tseslint from 'typescript-eslint';
+import github from 'eslint-plugin-github';
+
+export default tseslint.config([
+    github.getFlatConfigs().recommended,
+    ...github.getFlatConfigs().typescript,
+    {
+        ignores: ["**/dist/", "**/lib/", "**/node_modules/", "**/jest.config.js"],
+        plugins: {
+            "@typescript-eslint": typescriptEslint,
+            "@stylistic": stylistic,
+            "anti-trojan-source": antiTrojanSource,
+            jest,
+        },
+        languageOptions: {
+            globals: {
+                ...globals.jest,
+                ...jest.environments.globals.globals,
+                ...globals.node,
+            },
+            parser: tsParser,
+            ecmaVersion: 9,
+            sourceType: "module",
+            parserOptions: {
+                project: "./tsconfig.json",
+            },
+        },
+        rules: {
+            "@typescript-eslint/array-type": "error",
+            "@typescript-eslint/await-thenable": "error",
+            "@typescript-eslint/ban-ts-comment": "error",
+            "@typescript-eslint/consistent-type-assertions": "error",
+            "@typescript-eslint/explicit-function-return-type": ["error", {
+                allowExpressions: true,
+            }],
+            "@typescript-eslint/explicit-member-accessibility": ["error", {
+                accessibility: "no-public",
+            }],
+            "@stylistic/func-call-spacing": ["error", "never"],
+            "@typescript-eslint/no-array-constructor": "error",
+            "@typescript-eslint/no-empty-interface": "error",
+            "@typescript-eslint/no-explicit-any": "error",
+            "@typescript-eslint/no-extraneous-class": "error",
+            "@typescript-eslint/no-for-in-array": "error",
+            "@typescript-eslint/no-inferrable-types": "error",
+            "@typescript-eslint/no-misused-new": "error",
+            "@typescript-eslint/no-namespace": "error",
+            "@typescript-eslint/no-non-null-assertion": "warn",
+            "@typescript-eslint/no-require-imports": "error",
+            "@typescript-eslint/no-unnecessary-qualifier": "error",
+            "@typescript-eslint/no-unnecessary-type-assertion": "error",
+            "@typescript-eslint/no-unused-vars": "off",
+            "@typescript-eslint/no-useless-constructor": "error",
+            "@typescript-eslint/no-var-requires": "error",
+            "@typescript-eslint/prefer-for-of": "warn",
+            "@typescript-eslint/prefer-function-type": "warn",
+            "@typescript-eslint/prefer-includes": "error",
+            "@typescript-eslint/prefer-string-starts-ends-with": "error",
+            "@typescript-eslint/promise-function-async": "error",
+            "@typescript-eslint/require-array-sort-compare": "error",
+            "@typescript-eslint/restrict-plus-operands": "error",
+            "@stylistic/semi": ["error", "never"],
+            "@stylistic/type-annotation-spacing": "error",
+            "@typescript-eslint/unbound-method": "error",
+            "anti-trojan-source/no-bidi": "error",
+            camelcase: "off",
+            "eslint-comments/no-use": "off",
+            "github/filenames-match-regex": ["error", "^[a-z_]+(\\.test|\\.d)?$"],
+            "i18n-text/no-en": "off",
+            "importPlugin/no-namespace": "off",
+            "no-unused-vars": "off",
+            semi: "off",
+        },
+    }
+]);