Added support for staging and pushing external files

[rishabhsharma22]

Related Issues / Pull Requests

List all related issues and/or pull requests if there are any.

Description

Include a brief summary of the proposed changes.

What changes are proposed in this pull request?

• Bug fix (non-breaking change which fixes an issue).
• New feature (non-breaking change which adds functionality).
• Breaking change (fix or feature that would cause existing functionality to not work as expected; for instance,
  examples in this repository need to be updated too).
• This change requires a documentation update.

Checklist:

• My code follows the style guidelines of this project (PEP-8 with Google-style docstrings).
• My code modifies existing public API, or introduces new public API, and I updated or wrote docstrings that
  uses Google-style formatting and any other formatting that is supported by mkdocs and plugins this project
  uses.
• I have commented my code.
• My code requires documentation updates, and I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.

[annmary-roy]

This is breaking existing workflow. Please raise a new PR fixing the issue