fix: packages/test-utils/package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-TARFS-9535930

Author: snyk-io[bot]

packages/test-utils/package.json

@@ -45,11 +45,11 @@
     "start": "backstage-cli package start"
   },
   "dependencies": {
-    "@backstage/config": "workspace:^",
+    "@backstage/config": "0.1.1",
     "@backstage/core-app-api": "workspace:^",
-    "@backstage/core-plugin-api": "workspace:^",
+    "@backstage/core-plugin-api": "0.1.0",
     "@backstage/plugin-permission-common": "workspace:^",
-    "@backstage/plugin-permission-react": "workspace:^",
+    "@backstage/plugin-permission-react": "0.1.0",
     "@backstage/theme": "workspace:^",
     "@backstage/types": "workspace:^",
     "@material-ui/core": "^4.12.2",