dovecot: 2.3.0.1 -> 2.3.1

Semi-automatic update generated by https://github.com/ryantm/nix-update tools.

This update was made based on information from https://repology.org/metapackage/dovecot/versions.

These checks were done:

- built on NixOS
- ran `/nix/store/c20ip7wyymd39l7zisx38ky3bxp1sybv-dovecot-2.3.1/bin/dovecot --help` got 0 exit code
- ran `/nix/store/c20ip7wyymd39l7zisx38ky3bxp1sybv-dovecot-2.3.1/bin/dovecot --version` and found version 2.3.1
- found 2.3.1 with grep in /nix/store/c20ip7wyymd39l7zisx38ky3bxp1sybv-dovecot-2.3.1
- directory tree listing: https://gist.github.com/6d90467ee7649d7efc0a48eeacfc42c8

(cherry picked from commit a668ca4aac)

pkgs/servers/mail/dovecot/default.nix

@@ -8,7 +8,7 @@
 }:
 
 stdenv.mkDerivation rec {
-  name = "dovecot-2.3.0.1";
+  name = "dovecot-2.3.1";
 
   nativeBuildInputs = [ perl pkgconfig ];
   buildInputs =
@@ -20,7 +20,7 @@ stdenv.mkDerivation rec {
 
   src = fetchurl {
     url = "http://dovecot.org/releases/2.3/${name}.tar.gz";
-    sha256 = "0lzisrdgrj5qqwjb7bv99mf2aljm568r6g108yisp0s644z2nxxb";
+    sha256 = "14zva4f8k64x86sm9n21cp2yvrpph6k6k52bm22a00pxjwdq50q8";
   };
 
   preConfigure = ''