Set discovery.type.

Signed-off-by: dblock <[email protected]>

.github/workflows/test_unreleased.yml

@@ -51,8 +51,7 @@ jobs:
         working-directory: opensearch/distribution/archives/linux-tar/build/distributions
         run: |
           tar xf opensearch-min-*
-          echo "discovery.type: single-node" >> ./opensearch-*/config/opensearch.yml
-          ./opensearch-*/bin/opensearch &
+          ./opensearch-*/bin/opensearch -E discovery.type=single-node &
           for attempt in {1..20}; do sleep 5; if curl -s localhost:9200; then echo '=====> ready'; break; fi; echo '=====> waiting...'; done
       
       - name: Checkout PHP Client
@@ -73,7 +72,6 @@ jobs:
       - name: Wait for Search server
         run: php ./.github/wait_for_opensearch.php
 
-
       - name: Integration tests
         run: |
           composer run integration