Avoids running CI build on markdown or text file changes

[JBAhire]

Description

Earlier we were running CI on every single change including changes in README file which is not necessary at all.

As @adriancole suggested GitHub actions supports path filters which we can use to avoid running CI on changes in markdown or text files.

This PR adds path filters in GitHub action based CI running in this repo.

Testing

Tested with changes in GH action.

Checklist:

• [X] My changes generate no new warnings
• [X] I have added tests that prove my fix is effective or that my feature works
• [X] Any dependent changes have been merged and published in downstream modules

Documentation

References for this PR:

• https://github.community/t/using-on-push-tags-ignore-and-paths-ignore-together/16931
• https://docs.github.com/en/free-pro-team@latest/actions/reference/workflow-syntax-for-github-actions#filter-pattern-cheat-sheet