Update alpine Docker tag to v3.18
diff --git a/forks/hubzilla-docker/Dockerfile b/forks/hubzilla-docker/Dockerfile
index cca38e2..591ff3f 100644
--- a/forks/hubzilla-docker/Dockerfile
+++ b/forks/hubzilla-docker/Dockerfile
@@ -1,4 +1,4 @@
-FROM alpine:3.17
+FROM alpine:3.18
 MAINTAINER Silvio Fricke <silvio.fricke@gmail.com>
 
 ARG HUBZILLAVERSION=4.4.1