CHANGELOG.md in image_optimizer-1.7.2 vs CHANGELOG.md in image_optimizer-1.8.0

@@ -1,2 +1,5 @@
+## [1.8.0](https://github.com/jtescher/image_optimizer/releases/tag/v1.7.3) 2018-07-30
+* Fix: space in file name will break PNGQuantOptimizer - https://github.com/jtescher/image_optimizer/pull/21
+
 ## [1.7.2](https://github.com/jtescher/image_optimizer/releases/tag/v1.7.2) 2018-01-10
 * Added quiet option support for pngquant optimizer - https://github.com/jtescher/image_optimizer/pull/19