[ImgBot] Optimize images

*Total -- 1,569.11kb -> 1,520.50kb (3.1%)

/src/img/urbangarden-icon.png -- 6.15kb -> 2.68kb (56.42%)
/static/img/bruce-mars-8yg31xn4dsw-unsplash-1-.jpg -- 85.73kb -> 79.33kb (7.47%)
/static/img/brooke-cagle-norsyxmhgpi-unsplash-1-.jpg -- 146.97kb -> 141.19kb (3.93%)
/static/img/rui-silvestre-hamjpesmede-unsplash.jpg -- 190.17kb -> 183.21kb (3.66%)
/static/img/hust-wilson-njhvhxs4c0u-unsplash.jpg -- 54.27kb -> 52.74kb (2.83%)
/static/img/klaudia-piaskowska-g3lrnieizq4-unsplash.jpg -- 674.44kb -> 658.89kb (2.31%)
/static/img/joanna-nix-walkup-p7zgmc33s0u-unsplash.jpg -- 411.38kb -> 402.46kb (2.17%)

Signed-off-by: ImgBotApp <ImgBotHelp@gmail.com>

Author: ImgBotApp