[ImgBot] Optimize images

*Total -- 4,693.91kb -> 3,715.49kb (20.84%)

/assets/gk-icon.png -- 192.00kb -> 8.82kb (95.41%)
/assets/vs2017-08-change1.png -- 105.30kb -> 66.66kb (36.69%)
/assets/catalan1.png -- 15.30kb -> 9.88kb (35.45%)
/assets/dt1-publish1.png -- 44.92kb -> 29.24kb (34.89%)
/assets/dt1-status.png -- 34.29kb -> 22.70kb (33.79%)
/assets/vs2017-02-clone2.png -- 140.96kb -> 94.06kb (33.27%)
/assets/clone.png -- 70.78kb -> 47.91kb (32.32%)
/assets/vs2017-01-clone1.png -- 126.48kb -> 85.62kb (32.31%)
/assets/triangle_workflow.pt_br.png -- 66.46kb -> 46.15kb (30.56%)
/assets/fork.png -- 57.88kb -> 40.24kb (30.48%)
/assets/triangle_workflow.png -- 66.41kb -> 46.18kb (30.47%)
/assets/vs2017-10-commit2.png -- 56.20kb -> 39.23kb (30.19%)
/assets/vs2017-11-commit3.png -- 50.74kb -> 35.73kb (29.59%)
/assets/vs2017-04-branch1.png -- 45.22kb -> 32.43kb (28.29%)
/assets/vs2017-13-commit5.png -- 57.01kb -> 41.29kb (27.57%)
/assets/vs2017-05-branch2.png -- 47.98kb -> 34.75kb (27.57%)
/assets/vs2017-06-branch3.png -- 43.23kb -> 31.37kb (27.45%)
/assets/vscode-2018-08-clone.png -- 144.60kb -> 106.82kb (26.13%)
/assets/vs2017-07-branch4.png -- 40.49kb -> 30.08kb (25.72%)
/assets/vs2017-09-commit1.png -- 39.50kb -> 29.61kb (25.05%)
/assets/vs2017-03-clone3.png -- 59.00kb -> 45.38kb (23.08%)
/assets/vscode-2018-08-branch.png -- 132.05kb -> 101.85kb (22.87%)
/assets/vscode-2018-08-clone2.png -- 139.48kb -> 108.28kb (22.37%)
/assets/vscode-2018-08-clone1.png -- 135.49kb -> 105.27kb (22.3%)
/assets/vscode-2018-08-clone3.png -- 139.50kb -> 109.81kb (21.29%)
/assets/vs2017-12-commit4.png -- 46.00kb -> 36.48kb (20.7%)
/assets/vs2017-14-commit6.png -- 35.36kb -> 28.32kb (19.91%)
/assets/dt1-commit1.png -- 29.60kb -> 24.51kb (17.21%)
/assets/vscode-2018-08-gh-auth.png -- 13.07kb -> 10.91kb (16.49%)
/assets/join-slack-team.png -- 39.68kb -> 33.75kb (14.96%)
/assets/gk-branch.png -- 93.16kb -> 80.26kb (13.85%)
/assets/saasgrids-banner.png -- 157.20kb -> 136.07kb (13.44%)
/assets/compare-and-pull.png -- 90.51kb -> 78.84kb (12.9%)
/assets/dt-publish1.png -- 51.14kb -> 44.60kb (12.79%)
/assets/dt-commit2.png -- 50.77kb -> 44.40kb (12.54%)
/assets/gk-commit.png -- 55.22kb -> 48.32kb (12.51%)
/assets/gk-edit.png -- 95.68kb -> 83.75kb (12.47%)
/assets/dt-branch2.png -- 45.94kb -> 40.22kb (12.44%)
/assets/gk-push.png -- 97.61kb -> 85.52kb (12.38%)
/assets/dt-branch3.png -- 45.56kb -> 39.92kb (12.36%)
/assets/gk-stage.png -- 59.27kb -> 52.33kb (11.71%)
/assets/dt1-sign-in.png -- 15.62kb -> 13.85kb (11.36%)
/assets/dt-clone4.png -- 45.18kb -> 40.07kb (11.32%)
/assets/dt-branch1.png -- 47.03kb -> 41.71kb (11.31%)
/assets/dt1-create-branch-name.png -- 34.01kb -> 30.18kb (11.28%)
/assets/gk-login.png -- 44.17kb -> 39.30kb (11.03%)
/assets/pirate.png -- 16.27kb -> 14.52kb (10.76%)
/assets/dt1-commit2.png -- 32.76kb -> 29.30kb (10.56%)
/assets/dt-publish2.png -- 50.34kb -> 45.07kb (10.47%)
/assets/dt-sync.png -- 50.36kb -> 45.11kb (10.41%)
/assets/dt1-create-branch.png -- 14.76kb -> 13.25kb (10.18%)
/assets/vscode-2018-08-push.png -- 178.25kb -> 160.55kb (9.93%)
/assets/dt1-downloaded.png -- 29.33kb -> 26.54kb (9.53%)
/assets/vscode-2018-08-changes.png -- 195.96kb -> 177.52kb (9.41%)
/assets/dt-sync2.png -- 53.92kb -> 48.91kb (9.28%)
/assets/dt-status.png -- 38.39kb -> 34.82kb (9.28%)
/assets/vscode-2018-08-commit1.png -- 185.04kb -> 168.31kb (9.04%)
/assets/gk-clone.png -- 75.45kb -> 68.93kb (8.65%)
/assets/vscode-2018-08-commit.png -- 182.28kb -> 167.71kb (7.99%)
/assets/dt-clone1.png -- 28.00kb -> 25.96kb (7.29%)
/assets/dt-commit1.png -- 44.95kb -> 42.02kb (6.51%)
/assets/gk-origin.png -- 14.14kb -> 13.29kb (6.02%)
/assets/dt-clone3.png -- 45.25kb -> 42.63kb (5.79%)
/assets/dt-clone2.png -- 33.33kb -> 31.57kb (5.29%)
/assets/dt-sync3.png -- 62.03kb -> 59.59kb (3.94%)
/assets/dt1-clonetodesktop.png -- 13.40kb -> 12.98kb (3.12%)
/assets/dt1-open-githubdesktop.png -- 5.41kb -> 5.24kb (3.09%)
/assets/copy-to-clipboard.png -- 101.25kb -> 99.03kb (2.19%)