Add OSSF Scorecard GH Action and badge to README

[CyrilBaah]

• Improvement Area:
  Add OpenSSF Scorecard GitHub Action to automatically evaluate the security and best practices of the repository.

• Reasons:
  Integrating the OSSF Scorecard will help identify vulnerabilities, improve the code's security posture, and increase transparency for contributors and users.

• Benefits
  to help open source maintainers improve their security best practices and to help open source consumers judge whether their dependencies are safe.

[Fryguy]

We don't necessarily need to run it ourselves in GitHub Actions, because it's already being run by scorecard.dev. Here's crystal's scorecard: https://scorecard.dev/viewer/?uri=github.com/crystal-lang/crystal. However, running it ourselves would allow us to remove specific checks, such as fuzzing (since there is no fuzzing tool for crystal).

[CyrilBaah]

Ok, We can add an OpenSSF Scorecard badge to our README to showcase our project's security and compliance with open-source best practices. It provides real-time insight into the repository’s health and commitment to security like this