URL with percent-encoded # in README is not working on pub.dev

[JKRhb]

The README file of a package I am maintaining contains the following image URL pointing to a badge on shields.io:

https://img.shields.io/badge/Show%20Adopters%20and%20Users-%2331b8a3ff?logoColor=31b8a3ff

Note that before the first 31b8a3ff, there is a percent-encoded #, represented by %23.

When uploading the package to pub.dev, the URL above gets turned into

https://img.shields.io/badge/Show%20Adopters%20and%20Users-#31b8a3ff?logoColor=31b8a3ff

within the rendered README file, which causes the linked image to not be displayed correctly on pub.dev.

[isoos]

This is a bug in package:markdown, I've filed an issue here: dart-lang/tools#1457