fix badge in docs site

[yuki0410-dev]

Description

Linked issue: closes #4936

Problem See issue

Changes Change dependency badge to coverage badge to match readme

Contribution checklist

• [x] I have followed the contributing guidelines.
• [x] I have added sufficient test coverage for my changes.
• [x] I have formatted my code with Prettier and checked for linting issues with ESLint for code readability.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 96.67%. Comparing base (f90932c) to head (cfffd8e).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #4947 +/- ## ======================================= Coverage 96.67% 96.67% ======================================= Files 28 28 Lines 3275 3275 Branches 1357 1361 +4 ======================================= Hits 3166 3166 + Misses 109 105 -4 - Partials 0 4 +4 ```

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