[ImgBot] Optimize images (#4)

*Total -- 577.00kb -> 431.94kb (25.14%)

/images/tidyverse-hex.png -- 57.96kb -> 40.83kb (29.55%)
/images/FIP-book.png -- 17.15kb -> 12.14kb (29.21%)
/images/FIP-fg.png -- 459.87kb -> 342.60kb (25.5%)
/images/pitchlocation.png -- 42.02kb -> 36.37kb (13.45%)

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

Author: imgbot[bot]