Reduce the kubespray version from 2.20 to 2.19, because 2.20 requires ansible 5.7.1 which we don't have

Change-Id: I885bcfadc2841870ac0910d00d99fc421b012081
diff --git a/Makefile b/Makefile
index e1b001f..0ff5609 100644
--- a/Makefile
+++ b/Makefile
@@ -21,7 +21,7 @@
 TEST_APP_VALUES      ?= $(MAKEDIR)/5g-test-apps-values.yaml
 GET_HELM              = get_helm.sh
 
-KUBESPRAY_VERSION ?= release-2.20
+KUBESPRAY_VERSION ?= release-2.19
 DOCKER_VERSION    ?= '20.10'
 HELM_VERSION	  ?= v3.10.3
 KUBECTL_VERSION   ?= v1.23.15