feat: modification-header-check

[arsalan-datazip]

Why are the changes needed?

This PR adds a CI workflow that validates license.

Brief change log

GitHub Actions workflow that runs on push and pull requests, checks all modified files for required license headers

How was this patch tested?

• Add some test cases that check the changes thoroughly including negative and positive cases if possible

• Add screenshots for manual tests if appropriate

• Run test locally before making a pull request

[badalprasadsingh]

Check why the License check is failing on this PR.

Added first level review comments. Will review and test again in the next iteration.

[badalprasadsingh]

Will test this after these changes are made.

[badalprasadsingh]

There is one edge case:

If we delete a certain file, directory or module, which we eventually are going to do: There won't be any modification note. Let's discuss tomorrow on this.

Also, change the file name to modification-header-check.yml

[badalprasadsingh]

Cases Checked:

• renaming an existing file, will require modification check
• deleting a file or module, won't need any modification check
• creating a new file or modifying a file will require modification check (in first 40 lines)
• only runs for master and staging branch

One test case remains: if any file is .jpg, or .json we cannot add the modified line there. But in that case the PR owner, can add that case in the .yml workflow to skip those files, just like we do in integration tests.