Fix badge for build status

[kfule]

Description

The URL for the Shields.io badge for build status has been corrected.

Motivation and Context

I noticed that the build status badge is showing "repo or workflow not found" even though the test passed and the build is working properly.
I found out that this was due to the workflow yml being integrated.
08f5ccf

How Has This Been Tested?

I have checked that the badge on the revised URL can show the current, presumably correct status.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project.
• I have added tests to cover my changes.
• All new and existing tests passed.
• My change requires a documentation update, and I've opened a pull request to update it already:
• I have read https://mithril.js.org/contributing.html.