ol tag numbers color contrast

[Aniort]

Prerequisites

• I have searched for duplicate or closed issues
• I have validated any HTML to avoid common problems
• I have read the contributing guidelines

Describe the issue

Insufficiant contrast for the OL tag numbers, orange/white
these numbers cannot use the #f16e00 orange color on white background
Solution : orange --> black

Reduced test cases

https://boosted.orange.com/docs/5.1/components/list-group/#numbered

What operating system(s) are you seeing the problem on?

Windows

What browser(s) are you seeing the problem on?

Firefox

What version of Boosted are you using?

5.1