v2.3.0 released

[Timo Sirainen]

https://dovecot.org/releases/2.3/dovecot-2.3.0.tar.gz
https://dovecot.org/releases/2.3/dovecot-2.3.0.tar.gz.sig 

Some random notes:
 - This release is signed with a new PGP key 0x18A348AEED409DA1 (which is signed by the old key).
 - This fixes several compiling issues reported for the 2.3 release candidate. Also a few other fixes mainly for submission server and doveadm server.
 - We're still planning to make at least one (or two) more v2.2.x release before retiring it. It's now time for Christmas holidays though, so the next release will have to wait until the end of January.
 - We'll start distributing v2.3.x releases in apt/yum repositories in near future. There will be a separate email about it.

Some repetition from the release candidate's announcement:

There are several new and exciting features in v2.3.0. I'm especially happy about the new logging and statistics code, which will allow us to generate statistics for just about everything. We didn't have time to implement everything we wanted for them yet, and there especially aren't all that many logging events yet that can be used for statistics. We'll implement those to v2.3.1, which might also mean that some of the APIs might still change in v2.3.1 if that's required.

We also have new lib-smtp server code, which was used to implement SMTP submission server and do a partial rewrite for LMTP server.

Some of the larger changes:

 * Various setting changes, see https://wiki2.dovecot.org/Upgrading/2.3
 * Logging rewrite started: Logging is now based on hierarchical events.
   This makes it possible to do various things, like: 1) giving
   consistent log prefixes, 2) enabling debug logging with finer
   granularity, 3) provide logs in more machine readable formats
   (e.g. json). Everything isn't finished yet, especially a lot of the
   old logging code still needs to be translated to the new way.
 * Statistics rewrite started: Stats are now based on (log) events.
   It's possible to gather statistics about any event that is logged.
   See http://wiki2.dovecot.org/Statistics for details
 * ssl_dh setting replaces the old generated ssl-parameters.dat
 * IMAP: When BINARY FETCH finds a broken mails, send [PARSE] error
   instead of [UNKNOWNCTE]
 * Linux: core dumping via PR_SET_DUMPABLE is no longer enabled by
   default due to potential security reasons (found by cPanel Security
   Team).

 + Added support for SMTP submission proxy server, which includes
   support for BURL and CHUNKING extension.
 + LMTP rewrite. Supports now CHUNKING extension and mixing of
   local/proxy recipients.
 + auth: Support libsodium to add support for ARGON2I and ARGON2ID
   password schemes.
 + auth: Support BLF-CRYPT password scheme in all platforms
 + auth: Added LUA scripting support for passdb/userdb.
   See https://wiki2.dovecot.org/AuthDatabase/Lua
 - Input streams are more reliable now when there are errors or when
   the maximum buffer size is reached. Previously in some situations
   this could have caused Dovecot to try to read already freed memory.
 - Output streams weren't previously handling failures when writing a
   trailer at the end of the stream. This mainly affected encrypt and
   zlib compress ostreams, which could have silently written truncated
   files if the last write happened to fail (which shouldn't normally
   have ever happened).
 - virtual plugin: Fixed panic when fetching mails from virtual
   mailboxes with IMAP BINARY extension.
 - doveadm-server: Fix potential hangs with SSL connections
 - doveadm proxy: Reading commands' output from v2.2.33+ servers could
   have caused the output to be corrupted or caused a crash.
 - Many other smaller fixes