Ensure include FilePath in Windows has normalized separators

[AbrilRBS]

The issue and explanation is laid out in #305 (comment)
I'm creating this PR in hopes it helps anyone else facing the same issue.

I understand that the code might might not be fully production ready, or that a better approach might exist, I'd be happy to work towards a better solution after some guidance :)

Closes #305

Testing done

This was tested by running Jenkins with the compiled plugin and validating that a file was in fact uploaded. Before this change, we got a stacktrace when running in Windows. After, we have a file in our bucket. I can provide screenshots of the before/after if needed after some redaction

Submitter checklist

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did
• Link to relevant issues in GitHub or Jira
• Link to relevant pull requests, esp. upstream and downstream changes
• Ensure you have provided tests - that demonstrates feature works or fixes the issue

[joelsdc]

Please merge this 🙏 🙏