docs: limit PR preview building only when the documentation sources are updated #208
Description
Page / section
N/A - concerns the contribution experience to documentation
What should change?
We should only execute the `.github/workflows/preview-docs.yml` when the contribution updates the documentation sources.
In cases where it is not updated we should skip the preview and upload.Why?
Save resources - no need to run preview if we do not update docs.
Better contribution experience - no big comment with preview in the PR