[ImgBot] Optimize images (#2)

*Total -- 224.26kb -> 183.55kb (18.16%)

/doc-source/github-actions-checks.png -- 81.93kb -> 65.54kb (20.01%)
/doc-source/issue-templates.png -- 41.62kb -> 33.95kb (18.43%)
/doc-source/issue-bug-report.png -- 89.82kb -> 74.90kb (16.62%)
/doc-source/pull-request-labels.png -- 10.90kb -> 9.17kb (15.87%)

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

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

Author: imgbot[bot]