chore(deps): update dependency eslint-plugin-astro to ^0.21.0 (#8)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

Diff for: package.json

@@ -85,7 +85,7 @@
     "esbuild-register": "^3.3.3",
     "eslint": "^8.26.0",
     "eslint-config-prettier": "^8.5.0",
-    "eslint-plugin-astro": "^0.20.0",
+    "eslint-plugin-astro": "^0.21.0",
     "eslint-plugin-eslint-comments": "^3.2.0",
     "eslint-plugin-json-schema-validator": "^4.0.2",
     "eslint-plugin-jsonc": "^2.5.0",