Bump @typescript-eslint/eslint-plugin from 6.1.0 to 6.21.0 in /generator

Bumps [@typescript-eslint/eslint-plugin](https://github.com/typescript-eslint/typescript-eslint/tree/HEAD/packages/eslint-plugin) from 6.1.0 to 6.21.0.
- [Release notes](https://github.com/typescript-eslint/typescript-eslint/releases)
- [Changelog](https://github.com/typescript-eslint/typescript-eslint/blob/main/packages/eslint-plugin/CHANGELOG.md)
- [Commits](https://github.com/typescript-eslint/typescript-eslint/commits/v6.21.0/packages/eslint-plugin)

---
updated-dependencies:
- dependency-name: "@typescript-eslint/eslint-plugin"
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

generator/package-lock.json

@@ -27,7 +27,7 @@
     "@types/lodash": "^4.14.200",
     "@types/node": "^20.12.2",
     "@types/yargs": "^17.0.24",
-    "@typescript-eslint/eslint-plugin": "^6.1.0",
+    "@typescript-eslint/eslint-plugin": "^6.21.0",
     "@typescript-eslint/parser": "^6.9.1",
     "async": "^3.2.4",
     "autorest": "^3.6.3",