Update alpine-grafana.sh

Alpine 3.18

ct/alpine-grafana.sh

@@ -24,7 +24,7 @@ var_disk="0.5"
 var_cpu="1"
 var_ram="256"
 var_os="alpine"
-var_version="3.17"
+var_version="3.18"
 variables
 color
 catch_errors