[ImgBot] Optimize images

*Total -- 116.32kb -> 102.01kb (12.3%)

/man/figures/logo.png -- 45.52kb -> 38.76kb (14.85%)
/pkgdown/favicon/apple-touch-icon.png -- 16.94kb -> 15.03kb (11.25%)
/pkgdown/favicon/apple-touch-icon-180x180.png -- 16.94kb -> 15.03kb (11.25%)
/pkgdown/favicon/apple-touch-icon-76x76.png -- 5.94kb -> 5.29kb (10.98%)
/pkgdown/favicon/apple-touch-icon-152x152.png -- 13.79kb -> 12.39kb (10.19%)
/pkgdown/favicon/apple-touch-icon-120x120.png -- 10.33kb -> 9.28kb (10.15%)
/pkgdown/favicon/apple-touch-icon-60x60.png -- 4.61kb -> 4.15kb (9.93%)
/pkgdown/favicon/favicon-32x32.png -- 2.25kb -> 2.08kb (7.6%)

Signed-off-by: ImgBotApp <[email protected]>

Author: ImgBotApp