Rewrite github image links in README.md to use https://raw.githubusercontent.com

[vlladislav45]

The image is loaded properly in Github but not in pub.dev, here's my
README.md https://pub.dev/packages/flutter_advanced_canvas_editor,
and that's my library https://pub.dev/packages/flutter_advanced_canvas_editor .
I can't see the preview image, and I can't explain why.

The link is correct I've checked it twice.

[isoos]

@vlladislav45: You image link is https://github.com/Dojibery/flutter-advanced-canvas-editor/blob/master/assets/images/preview.png and if you open that link, it is a HTML page on github, and not an image content blob. GitHub, during the markdown rendering rewrites it to https://raw.githubusercontent.com/Dojibery/flutter-advanced-canvas-editor/master/assets/images/preview.png which is a proper image blob, and the browser will display it.

We may consider to also do such rewrite in case we detect image links, and I'll keep the issue open for that reason.

[Yihun-Alemayehu]

Hi! I’d like to work on this and submit a PR if that’s okay.
The rewrite logic seems clear from the discussion above.