upgrade alpine base image to v3.15.0 including upgrade of openssh-server package to v8.8p1 and rsync package to v3.2.3-r5 (see below)

https://web.archive.org/web/20211204063543/https://www.openssh.com/releasenotes.html
https://git.alpinelinux.org/aports/commit/main/openssh?h=3.15-stable&id=8293eb79d181515827092ec15f9dcb24989959c6
https://git.alpinelinux.org/aports/commit/main/openssh?h=3.15-stable&id=e05faf293fd802c729d432906ffb5e8db77f3830
https://git.alpinelinux.org/aports/commit/main/openssh?h=3.15-stable&id=b5e3d52e5a95ff8a73c23908201474bb15048a11

https://github.com/fphammerle/docker-sftpd/commit/fc472ac4fbc12a25e8831cab197711104923b775

https://git.alpinelinux.org/aports/commit/main/rsync?h=3.15-stable&id=277716a1acbe18a0f2411b2e9b93b8d160204bbf

Dockerfile

@@ -1,7 +1,7 @@
-FROM alpine:3.14.3
+FROM docker.io/alpine:3.15.0
 
-ARG RSYNC_PACKAGE_VERSION=3.2.3-r4
-ARG OPENSSH_SERVER_PACKAGE_VERSION=8.6_p1-r3
+ARG RSYNC_PACKAGE_VERSION=3.2.3-r5
+ARG OPENSSH_SERVER_PACKAGE_VERSION=8.8_p1-r1
 RUN apk add --no-cache \
     openssh-server=$OPENSSH_SERVER_PACKAGE_VERSION \
     rrsync=$RSYNC_PACKAGE_VERSION \

openssh-package-log.url

@@ -1 +1 @@
-https://git.alpinelinux.org/aports/log/main/openssh
+https://git.alpinelinux.org/aports/log/main/openssh?h=3.15-stable

rsync-package-log.url

@@ -1 +1 @@
-https://git.alpinelinux.org/aports/log/main/rsync
+https://git.alpinelinux.org/aports/log/main/rsync?h=3.15-stable