[CI] - Setup a CI build for this python project using GitHub Actions

[nirmalchandra]

AC1:
Setup a CI build for this python project using GitHun action

AC2:
Verify it has run for this new PR. Check the "Checks" tab in the PR here.

[ambicuity]

✅ CI workflow has been created in PR #8!

The workflow includes:

• Tests on Python 3.9, 3.10, and 3.11
• Runs both unit tests and integration tests
• Generates coverage reports
• Automatically triggered on push and pull requests to main branch

Once the PR is merged, the CI will automatically run on all future PRs and pushes to the main branch.

[nirmalchandra]

CI Failure 🔴 (all 3 python versions), but it could be minor ones.
here : https://github.com/SUPAIDEAS/passifypdf/actions/runs/18777306715/job/53574790757

@ambicuity , can you have a look?

[ambicuity]

Resolved by adding a GitHub Actions CI workflow in .github/workflows/ci.yml.