For elastic integration tests use images built in the CI (#215)

* For elastic integration tests use images built in the CI

Rather than downloading the elastic images from the ghcr for the
integration tests we use container images built during the CI
integration test check. This allows us to check if any changes to the
services breaks anything.

* Use env vars in build cmd instead of mutating env vars with sed

Author: osullivandonal

.github/workflows/run-integration-tests-elastic.yml

@@ -31,6 +31,10 @@ jobs:
       with:
           version: latest
 
+    - name: Build images from source
+      run: |
+        IMAGE_NAME=otel-demo-integration-tests DEMO_VERSION=test docker compose --env-file .env --env-file .env.override build --parallel
+
     - name: Create k8s Kind Cluster
       uses: helm/kind-action@v1