Add GitHub Action for Running Unit Tests on Multiple OSs

[sagar3181]

Given we are using github,
whenever code is pushed to the repository or a pull request is opened,
then unit tests on multiple operating systems.

Need to set up a GitHub Action that automatically runs our unit tests on multiple operating systems (Windows, macOS, and Linux) whenever code is pushed to the repository or a pull request is opened.

Acceptance Criteria:

• There is a Github workflow running unit tests:
  • When code is pushed to repo.
  • When a pull request is open.
• Runs on the following OS:
  • Windows
  • macOS
  • Linux