Use void logger in test.

plugins/search-backend-node/package.json

@@ -23,6 +23,7 @@
     "winston": "^3.2.1"
   },
   "devDependencies": {
+    "@backstage/backend-common": "0.5.6",
     "@backstage/cli": "^0.6.0"
   },
   "files": [

plugins/search-backend-node/src/index.test.ts

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+import { getVoidLogger } from '@backstage/backend-common';
 import {
   DocumentCollator,
   DocumentDecorator,
@@ -39,7 +40,7 @@ describe('IndexBuilder', () => {
   let testDecorator: DocumentDecorator;
 
   beforeEach(() => {
-    testIndexBuilder = new IndexBuilder();
+    testIndexBuilder = new IndexBuilder({ logger: getVoidLogger() });
     testCollator = new TestDocumentCollator();
     testDecorator = new TestDocumentDecorator();
   });