[ImgBot] Optimize images

*Total -- 201.93kb -> 142.81kb (29.28%)

/extensions/npm/images/npm_icon.png -- 3.21kb -> 0.51kb (84.1%)
/src/vs/workbench/parts/debug/electron-browser/media/stepout-tb.png -- 2.89kb -> 0.47kb (83.83%)
/src/vs/workbench/parts/debug/electron-browser/media/stop-tb.png -- 1.50kb -> 0.35kb (76.43%)
/src/vs/workbench/parts/debug/electron-browser/media/pause-tb.png -- 1.55kb -> 0.37kb (76.34%)
/src/vs/workbench/browser/parts/editor/media/forward-tb.png -- 1.57kb -> 0.37kb (76.25%)
/src/vs/workbench/browser/parts/editor/media/back-tb.png -- 1.52kb -> 0.37kb (75.53%)
/src/vs/workbench/parts/debug/electron-browser/media/continue-tb.png -- 1.60kb -> 0.42kb (73.48%)
/src/vs/workbench/parts/debug/electron-browser/media/stepinto-tb.png -- 1.66kb -> 0.47kb (71.51%)
/src/vs/workbench/parts/debug/electron-browser/media/restart-tb.png -- 1.91kb -> 0.59kb (68.84%)
/src/vs/workbench/parts/debug/electron-browser/media/stepover-tb.png -- 1.93kb -> 0.62kb (67.75%)
/resources/linux/code.png -- 5.76kb -> 2.66kb (53.86%)
/extensions/html-language-features/icons/html.png -- 4.40kb -> 2.28kb (48.15%)
/extensions/theme-seti/icons/seti-circular-128x128.png -- 8.73kb -> 4.70kb (46.12%)
/extensions/typescript-language-features/icon.png -- 1.60kb -> 0.97kb (39.15%)
/src/vs/platform/extensionManagement/node/media/defaultIcon.png -- 1.65kb -> 1.03kb (37.49%)
/src/vs/workbench/parts/extensions/electron-browser/media/defaultIcon.png -- 1.65kb -> 1.03kb (37.49%)
/extensions/vscode-api-tests/testWorkspace/sub/image.png -- 35.87kb -> 24.99kb (30.33%)
/extensions/vscode-api-tests/testWorkspace/image.png -- 35.87kb -> 24.99kb (30.33%)
/resources/win32/code_150x150.png -- 0.55kb -> 0.39kb (29.96%)
/extensions/css-language-features/icons/css.png -- 5.07kb -> 3.63kb (28.37%)
/extensions/json-language-features/icons/json.png -- 5.84kb -> 4.33kb (25.89%)
/extensions/markdown-language-features/icon.png -- 1.19kb -> 0.88kb (25.86%)
/src/vs/workbench/parts/extensions/electron-browser/media/theme-icon.png -- 9.90kb -> 7.42kb (25.1%)
/extensions/php-language-features/icons/logo.png -- 10.85kb -> 8.99kb (17.13%)
/extensions/gulp/images/gulp.png -- 7.36kb -> 6.20kb (15.8%)
/extensions/merge-conflict/resources/icons/merge-conflict.png -- 2.47kb -> 2.10kb (14.96%)
/extensions/jake/images/cowboy_hat.png -- 43.85kb -> 41.67kb (4.98%)