Merge #2099

2099: update Dockerfile to alpine 3.14.3 r=mergify[bot] a=willofr

## What type of PR?
Security fix

## What does this PR do?
Updated the Dockerfile to use the latest alpine version 3.14.3 where several CVEs have been fixed: https://alpinelinux.org/posts/Alpine-3.14.3-released.html
New images successfully built on my test env.

### Related issue(s)
None

## Prerequisites
Before we can consider review and merge, please make sure the following list is done and checked.
If an entry in not applicable, you can check it or remove it from the list.

- [x] In case of feature or enhancement: documentation updated accordingly
- [x] Unless it's docs or a minor change: add [changelog](https://mailu.io/master/contributors/workflow.html#changelog) entry file.


Co-authored-by: Will <will@packer-output-c8fcfb40-3d93-4475-8f87-e14a9dd683b6>
Co-authored-by: willofr <willofr@users.noreply.github.com>

core/admin/Dockerfile

@@ -1,5 +1,5 @@
 # First stage to build assets
-ARG DISTRO=alpine:3.14.2
+ARG DISTRO=alpine:3.14.3
 ARG ARCH=""
 
 FROM ${ARCH}node:16 as assets

core/dovecot/Dockerfile

@@ -1,4 +1,4 @@
-ARG DISTRO=alpine:3.14.2
+ARG DISTRO=alpine:3.14.3
 
 FROM $DISTRO
 ARG VERSION

core/nginx/Dockerfile

@@ -1,4 +1,4 @@
-ARG DISTRO=alpine:3.14.2
+ARG DISTRO=alpine:3.14.3
 FROM $DISTRO
 ARG VERSION
 

core/none/Dockerfile

@@ -1,6 +1,6 @@
 # This is an idle image to dynamically replace any component if disabled.
 
-ARG DISTRO=alpine:3.14.2
+ARG DISTRO=alpine:3.14.3
 FROM $DISTRO
 
 CMD sleep 1000000d

core/postfix/Dockerfile

@@ -1,4 +1,4 @@
-ARG DISTRO=alpine:3.14.2
+ARG DISTRO=alpine:3.14.3
 
 FROM $DISTRO
 ARG VERSION

optional/clamav/Dockerfile

@@ -1,4 +1,4 @@
-ARG DISTRO=alpine:3.14.2
+ARG DISTRO=alpine:3.14.3
 FROM $DISTRO
 ARG VERSION
 

optional/fetchmail/Dockerfile

@@ -1,4 +1,4 @@
-ARG DISTRO=alpine:3.14.2
+ARG DISTRO=alpine:3.14.3
 FROM $DISTRO
 ARG VERSION
 

optional/radicale/Dockerfile

@@ -1,4 +1,4 @@
-ARG DISTRO=alpine:3.14.2
+ARG DISTRO=alpine:3.14.3
 FROM $DISTRO
 ARG VERSION
 

optional/unbound/Dockerfile

@@ -1,4 +1,4 @@
-ARG DISTRO=alpine:3.14.2
+ARG DISTRO=alpine:3.14.3
 FROM $DISTRO
 ARG VERSION
 

setup/Dockerfile

@@ -1,4 +1,4 @@
-ARG DISTRO=alpine:3.14.2
+ARG DISTRO=alpine:3.14.3
 FROM $DISTRO
 ARG VERSION
 ENV TZ Etc/UTC

towncrier/newsfragments/2099.bugfix

@@ -0,0 +1 @@
+updated Dockerfile to alpine 3.14.3 to address several CVEs