[ImgBot] optimizes images

*Total -- 1,932.09kb -> 1,753.28kb (9.25%)

/images/promise states and fates.png -- 51.19kb -> 23.98kb (53.16%)
/images/github.png -- 1.67kb -> 1.08kb (35.65%)
/images/atomts.png -- 15.11kb -> 12.79kb (15.34%)
/cover.jpg -- 1,828.25kb -> 1,682.17kb (7.99%)
/images/venn.png -- 35.86kb -> 33.26kb (7.23%)

Author: ImgBotApp