Bump send and express (#596)

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Author: dependabot[bot]

package-lock.json

@@ -98,7 +98,7 @@
     "connect-redis": "^7.1.1",
     "cookie-parser": "^1.4.6",
     "csurf": "^1.11.0",
-    "express": "^4.19.2",
+    "express": "^4.21.0",
     "express-prom-bundle": "^7.0.0",
     "express-session": "^1.18.0",
     "govuk-frontend": "^5.5.0",