fix(deps): update astro monorepo

Author: renovate[bot]

package.json

@@ -17,11 +17,11 @@
 	},
 	"dependencies": {
 		"@astrojs/markdown-remark": "^6.3.10",
-		"@astrojs/mdx": "4.3.13",
-		"@astrojs/rss": "4.0.15",
-		"@astrojs/sitemap": "3.7.0",
+		"@astrojs/mdx": "4.3.14",
+		"@astrojs/rss": "4.0.18",
+		"@astrojs/sitemap": "3.7.2",
 		"@tailwindcss/vite": "4.1.18",
-		"astro": "5.17.1",
+		"astro": "5.18.1",
 		"astro-expressive-code": "^0.41.6",
 		"astro-icon": "^1.1.5",
 		"astro-robots-txt": "^1.0.0",