perf: [ImgBot] optimize images (#1590)

*Total -- 2,702.61kb -> 2,104.73kb (22.12%)

/.github/images/code-custom.png -- 668.04kb -> 495.95kb (25.76%)
/.github/images/code.png -- 666.07kb -> 502.98kb (24.49%)
/.github/images/mdx.png -- 649.64kb -> 519.91kb (19.97%)
/.github/images/mdx-custom.png -- 680.68kb -> 547.72kb (19.53%)
/public/images/logo.svg -- 38.17kb -> 38.17kb (0.01%)

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

Author: imgbot[bot]