upgrade postfix package from v3.6.1-r0 to v3.6.2-r0 (see links below)

http://www.postfix.org/announcements/postfix-3.6.2.html
https://git.alpinelinux.org/aports/commit/main/postfix?id=bc20b6e838249576971d8faa39fc7492555045c2

Dockerfile

@@ -1,6 +1,6 @@
 FROM alpine:3.14.0
 
-ARG POSTFIX_PACKAGE_VERSION=3.6.1-r0
+ARG POSTFIX_PACKAGE_VERSION=3.6.2-r0
 # http://www.postfix.org/postconf.5.html#tls_append_default_CA
 # https://www.mozilla.org/en-US/about/governance/policies/security-group/certs/
 ARG MOZILLA_CA_CERT_STORE_PACKAGE_VERSION=20191127-r5