fix: plugins/techdocs-addons-test-utils/package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-HTTPPROXYMIDDLEWARE-9691387
- https://snyk.io/vuln/SNYK-JS-HTTPPROXYMIDDLEWARE-9691389

Author: snyk-io[bot]

plugins/techdocs-addons-test-utils/package.json

@@ -38,10 +38,10 @@
     "@backstage/integration-react": "workspace:^",
     "@backstage/plugin-catalog": "workspace:^",
     "@backstage/plugin-search-react": "workspace:^",
-    "@backstage/plugin-techdocs": "workspace:^",
+    "@backstage/plugin-techdocs": "0.1.1",
     "@backstage/plugin-techdocs-react": "workspace:^",
-    "@backstage/test-utils": "workspace:^",
-    "@backstage/theme": "workspace:^",
+    "@backstage/test-utils": "0.1.1",
+    "@backstage/theme": "0.1.1",
     "@material-ui/core": "^4.12.2",
     "@material-ui/icons": "^4.9.1",
     "@material-ui/lab": "4.0.0-alpha.61",