Bump to ESLint 9 (#606)

This bumps to ESLint 9:

* Bump the main `eslint` package to v9
* Remove the `eslint-config-standard` package as it doesn't yet support
  ESLint 9 and doesn't appear to be actively maintained... I considered
  some of the alternatives, but they've got some drama attached (https://github.com/standard/standard/issues/1948)
  so it seemed simplest for now to not worry about replacing it. This is
  a linter, so it's easy to switch to a different config if we want to
  later.
* Migrate to the new [Flat config format](https://eslint.org/docs/user-guide/configuring/configuration-files#using-the-flat-format).

package.json

@@ -28,18 +28,20 @@
     "pluralize": "^8.0.0"
   },
   "devDependencies": {
+    "@eslint/eslintrc": "^3.3.0",
+    "@eslint/js": "^9.22.0",
     "@types/jest": "^29.5.12",
     "@types/node": "^20.11.20",
     "@types/yargs": "^17.0.32",
-    "@typescript-eslint/eslint-plugin": "^7.0.2",
-    "@typescript-eslint/parser": "^7.0.2",
+    "@typescript-eslint/eslint-plugin": "^8.27.0",
+    "@typescript-eslint/parser": "^8.27.0",
     "@vercel/ncc": "^0.38.3",
     "dotenv": "^16.4.5",
-    "eslint": "^8.50.0",
-    "eslint-config-standard": "^17.1.0",
-    "eslint-plugin-import": "^2.29.1",
+    "eslint": "^9.22.0",
+    "eslint-plugin-import": "^2.31.0",
     "eslint-plugin-node": "^11.1.0",
-    "eslint-plugin-promise": "^6.1.1",
+    "eslint-plugin-promise": "^7.2.1",
+    "globals": "^16.0.0",
     "jest": "^29.7.0",
     "nock": "^13.5.3",
     "ts-jest": "^29.1.2",