fix(deps): update dependency express to ^4.21.2

Author: renovate[bot]

packages/gatsby/package.json

@@ -83,7 +83,7 @@
     "eslint-webpack-plugin": "^2.7.0",
     "event-source-polyfill": "1.0.31",
     "execa": "^5.1.1",
-    "express": "^4.18.2",
+    "express": "^4.21.2",
     "express-http-proxy": "^1.6.3",
     "fastest-levenshtein": "^1.0.16",
     "fastq": "^1.15.0",