Update logstash.yml

Author: Chris Wiechmann

.github/workflows/logstash.yml

@@ -44,4 +44,6 @@ jobs:
       env:
         API_BUILDER_URL: 'http://localhost:8080'
         MEMCACHED: 'localhost:11211'
-        API_BUILDER_SSL_CERT: ""
+        # This is not relevant as we test with HTTP
+        # But it's required by Logstash to be a valid certificate
+        API_BUILDER_SSL_CERT: "./certificates/api-builder.crt"