added dovecot lmtp server

> master: Fatal: service(lmtp) access(/usr/libexec/dovecot/lmtp) failed: No such file or directory

CHANGELOG.md

@@ -5,6 +5,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+- dovecot lmtp server
+  ( https://doc.dovecot.org/configuration_manual/protocols/lmtp_server/ )
+
 ### Changed
 - upgrade base image: alpine v3.10 -> v3.11
 

Dockerfile

@@ -1,7 +1,9 @@
 FROM alpine:3.11
 
 ARG DOVECOT_PACKAGE_VERSION=2.3.9.3-r0
-RUN apk add --no-cache dovecot=$DOVECOT_PACKAGE_VERSION \
+RUN apk add --no-cache \
+        dovecot-lmtpd=$DOVECOT_PACKAGE_VERSION \
+        dovecot=$DOVECOT_PACKAGE_VERSION \
     && find /etc/ssl/dovecot -type f -print -delete
 
 VOLUME /etc/ssl/dovecot