Update to commit a175521 from git@github.com:gedex/wp-slack.git

Includes the following commit(s):

commit a1755217e48228b86b39b636394b44683a5cb5f3
Author: Akeda Bagus <akeda@x-team.com>

    Added release in changelog.

M	readme.md
M	readme.txt

commit 7b2d8e87186288ab9777f7492626a9c82d5526ce
Author: Akeda Bagus <akeda@x-team.com>

    Bump to version 0.2.0.

M	includes/plugin.php
M	slack.php

commit 443f758b2b5a541621308d51efc41644953ff887
Author: Akeda Bagus <akeda@x-team.com>

    Added plugin banner.

A	assets/banner-1544x500.png
A	assets/banner-772x250.png
M	readme.md

commit 460ea40c2ccacc5d302dd20bfdc648380fd633be
Author: Akeda Bagus <akeda@x-team.com>

    For builtin events only notify if post type is 'post'.

M	includes/event-manager.php

commit 5fbcfebb89944897bf829deb23bbb20bd23077d7
Author: Akeda Bagus <akeda@x-team.com>

    Added Slack link.

M	readme.md
M	readme.txt


git-svn-id: https://plugins.svn.wordpress.org/slack/trunk@892359 b8457f37-d9ea-0310-8a92-e5e31aec5664