Makefile: Update the cluster version to 7.8-SNAPSHOT

Author: karmi

Makefile

@@ -247,7 +247,7 @@ godoc: ## Display documentation for the package
 	godoc --http=localhost:6060 --play
 
 cluster: ## Launch an Elasticsearch cluster with Docker
-	$(eval version ?= "elasticsearch-oss:7.x-SNAPSHOT")
+	$(eval version ?= "elasticsearch-oss:7.8-SNAPSHOT")
 ifeq ($(origin nodes), undefined)
 	$(eval nodes = 1)
 endif
@@ -327,7 +327,7 @@ ifdef detach
 endif
 
 cluster-update: ## Update the Docker image
-	$(eval version ?= "elasticsearch-oss:7.x-SNAPSHOT")
+	$(eval version ?= "elasticsearch-oss:7.8-SNAPSHOT")
 	@printf "\033[2m→ Updating the Docker image...\033[0m\n"
 	@docker pull docker.elastic.co/elasticsearch/$(version);