Bump stable tag

Author: tijmenbruggeman

readme.txt

@@ -4,7 +4,7 @@ Donate link: https://tinypng.com/
 Tags: compress images, compression, image size, page speed, performance
 Requires at least: 4.0
 Tested up to: 6.8
-Stable tag: 3.6.0
+Stable tag: 3.6.1
 License: GPLv2 or later
 License URI: http://www.gnu.org/licenses/gpl-2.0.html