fix: package.json & yarn.lock to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-BODYPARSER-7926860
- https://snyk.io/vuln/SNYK-JS-EXPRESS-7926867
- https://snyk.io/vuln/SNYK-JS-SEND-7926862
- https://snyk.io/vuln/SNYK-JS-SERVESTATIC-7926865

package.json

@@ -22,7 +22,7 @@
     "awesomplete": "^1.1.2",
     "bootstrap": "^4.4.1",
     "cookie": "^0.3.1",
-    "express": "^4.16.2",
+    "express": "^4.21.0",
     "fast-deep-equal": "^2.0.1",
     "frappe-charts": "^1.5.8",
     "frappe-datatable": "^1.14.0",