Bump alpine from 3.17.2 to 3.17.3 (#43)

Dockerfile

@@ -1,4 +1,4 @@
-FROM docker.io/alpine:3.17.2
+FROM docker.io/alpine:3.17.3
 
 ARG BORGBACKUP_PACKAGE_VERSION=1.2.2-r1
 ARG OPENSSH_SERVER_PACKAGE_VERSION=9.1_p1-r2