fix: plugins/github-pull-requests-board/package.json to reduce vulnerabilities

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

Author: snyk-io[bot]

plugins/github-pull-requests-board/package.json

@@ -38,7 +38,7 @@
     "@backstage/core-components": "workspace:^",
     "@backstage/core-plugin-api": "workspace:^",
     "@backstage/integration": "workspace:^",
-    "@backstage/plugin-catalog-react": "workspace:^",
+    "@backstage/plugin-catalog-react": "1.0.0",
     "@backstage/theme": "workspace:^",
     "@material-ui/core": "^4.12.2",
     "@material-ui/icons": "^4.9.1",