Add a pause after deploying test db containers as a temporary kludge

tests/run-tests.sh

@@ -41,6 +41,14 @@ do
     # Specify the version we're testing against
     export PGTAG="${images["$version"]}"
 
+    # Start the db container first and wait a moment for it to initialize
+    # This isn't perfect, but if the health check catches PostgreSQL when it's
+    # first being initialized, the agent can fail to connect.
+    # A better solution would probably be to make the agent retry more.
+    docker compose up -d db
+
+    sleep 2
+
     # Start the containers
     docker compose up --exit-code-from=agent agent
     rc=$?