Use 9.4 as the default e2e-tests Solr version (#645)

diff --git a/tests/scripts/manage_e2e_tests.sh b/tests/scripts/manage_e2e_tests.sh
index cc00142..c42b92f 100755
--- a/tests/scripts/manage_e2e_tests.sh
+++ b/tests/scripts/manage_e2e_tests.sh
@@ -76,7 +76,7 @@
   KUBERNETES_VERSION="v1.26.6"
 fi
 if [[ -z "${SOLR_IMAGE:-}" ]]; then
-  SOLR_IMAGE="${SOLR_VERSION:-8.11.2}"
+  SOLR_IMAGE="${SOLR_VERSION:-9.4.0}"
 fi
 if [[ "${SOLR_IMAGE}" != *":"* ]]; then
   SOLR_IMAGE="solr:${SOLR_IMAGE}"