Migrate to ESLint flat config for eslint-plugin-github 6.x compatibility

Co-authored-by: jonrohan <54012+jonrohan@users.noreply.github.com>

Author: Copilot

.eslintignore

@@ -0,0 +1,39 @@
+import eslintPluginGithub from 'eslint-plugin-github'
+import globals from 'globals'
+
+export default [
+  {
+    ignores: ['coverage/', 'node_modules/', 'dist/', '__tests__/__fixtures__/', 'rollup.config.js'],
+  },
+  {
+    ...eslintPluginGithub.getFlatConfigs().recommended,
+    languageOptions: {
+      ecmaVersion: 2023,
+      sourceType: 'module',
+      globals: {
+        ...globals.node,
+        ...globals.es6,
+      },
+    },
+    rules: {
+      ...eslintPluginGithub.getFlatConfigs().recommended.rules,
+      'import/no-commonjs': 'off',
+      'github/no-then': 'off',
+      'i18n-text/no-en': 'off',
+      'import/extensions': ['error', 'ignorePackages'],
+    },
+  },
+  {
+    files: ['__tests__/**/*.js'],
+    languageOptions: {
+      globals: {
+        ...globals.jest,
+        testRule: 'readonly',
+        testRuleConfigs: 'readonly',
+      },
+    },
+    rules: {
+      'import/no-named-as-default-member': 'off',
+    },
+  },
+]

.eslintrc.json

@@ -65,10 +65,11 @@
     "@typescript-eslint/parser": "^8.0.1",
     "dedent": "^1.5.3",
     "eslint": "^8.57.1",
-    "eslint-plugin-github": "^5.1.4",
+    "eslint-plugin-github": "^6.0.0",
     "eslint-plugin-import": "^2.29.1",
     "eslint-plugin-jest": "^29.2.1",
     "eslint-plugin-prettier": "^5.1.3",
+    "globals": "^17.2.0",
     "jest": "^30.2.0",
     "jest-preset-stylelint": "^8.0.0",
     "prettier": "^3.2.5",