Add GitHub Actions CI badge to README

[manisha-goyal]

As a developer I need to add a CI badge to the README file So that everyone can see the current build status of the project

Details and Assumptions

• The badge will be added to the README.md file
• The badge will display the build status (e.g., passing or failing)
• The shopcarts service is hosted on Git
• The GitHub Actions workflow for running unit tests and checking code quality has been set up

• The GitHub Actions CI badge URL is available

  Acceptance Criteria

  Given a shopcarts service repository with a GitHub Actions CI workflow
  When the workflow is running
  Then the README.md file should display a badge showing the current build status

[RogerHuangPKX]

We can customize our own badges and add a few highlight here. Please refer this image.