Bump alpine from 3.18.0 to 3.18.2 (#47)

Dockerfile

@@ -1,4 +1,4 @@
-FROM docker.io/alpine:3.18.0
+FROM docker.io/alpine:3.18.2
 
 ARG BORGBACKUP_PACKAGE_VERSION=1.2.4-r4
 ARG OPENSSH_SERVER_PACKAGE_VERSION=9.3_p1-r3