fix: plugins/stack-overflow-backend/package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-AJV-15274295
- https://snyk.io/vuln/SNYK-JS-QS-15268416

Author: snyk-bot

plugins/stack-overflow-backend/package.json

@@ -32,11 +32,11 @@
     "clean": "backstage-cli package clean"
   },
   "dependencies": {
-    "@backstage/backend-common": "workspace:^",
+    "@backstage/backend-common": "0.24.1",
     "@backstage/config": "workspace:^",
-    "@backstage/plugin-search-common": "workspace:^",
+    "@backstage/plugin-search-common": "0.3.1",
     "node-fetch": "^2.6.7",
-    "qs": "^6.9.4",
+    "qs": "^6.14.2",
     "winston": "^3.2.1"
   },
   "devDependencies": {