You can use https://shields.io/, as described in alexandresanlim/Badges4-README.md-Profile
, in order to add any badge you need.
For a project README, you can "add a workflow status badge", or use another action like actions/dynamic-badges
in order to display the right value and color for a given service:
The idea behind using a GitHub Action is to update those badge automatically during a build, after for instance a push to your repository.