[dovecot/pigeonhole] 183bc5: Added v0.4.18 to NEWS.

[GitHub]

  Branch: refs/heads/release-0.4.19
  Home:   https://github.com/dovecot/pigeonhole
  Commit: 183bc5b927ddd06e04a398acedffb14927f8a9d1
      https://github.com/dovecot/pigeonhole/commit/183bc5b927ddd06e04a398acedffb14927f8a9d1
  Author: Stephan Bosch <stephan.bosch at dovecot.fi>
  Date:   2017-05-24 (Wed, 24 May 2017)

  Changed paths:
    M NEWS

  Log Message:
  -----------
  Added v0.4.18 to NEWS.