upgrade rsync packages from v3.2.3-r2 to v3.2.3-r4 (see links below)

https://git.alpinelinux.org/aports/commit/main/rsync?id=277716a1acbe18a0f2411b2e9b93b8d160204bbf
https://git.alpinelinux.org/aports/commit/main/rsync?id=e34ba444626c002a8d4ef71ab1c33ced59b45bf6

Dockerfile

@@ -1,6 +1,6 @@
 FROM alpine:3.14.0
 
-ARG RSYNC_PACKAGE_VERSION=3.2.3-r2
+ARG RSYNC_PACKAGE_VERSION=3.2.3-r4
 ARG OPENSSH_SERVER_PACKAGE_VERSION=8.6_p1-r2
 RUN apk add --no-cache \
     openssh-server=$OPENSSH_SERVER_PACKAGE_VERSION \