Prepare release of version 1.8.0 (#1649)

https://github.com/FreshRSS/FreshRSS/milestone/24

CHANGELOG.md

@@ -1,6 +1,6 @@
 # Changelog
 
-## 2017-XX-XX FreshRSS 1.7.1-dev
+## 2017-10-01 FreshRSS 1.8.0
 
 * Compatibility:
 	* Minimal PHP version increased to PHP 5.3.8+ to fix sanitize bug [#1604](https://github.com/FreshRSS/FreshRSS/issues/1604)

constants.php

@@ -1,5 +1,5 @@
 <?php
-define('FRESHRSS_VERSION', '1.7.1-dev');
+define('FRESHRSS_VERSION', '1.8.0');
 define('FRESHRSS_WEBSITE', 'https://freshrss.org');
 define('FRESHRSS_WIKI', 'https://freshrss.github.io/FreshRSS/');