Preview builds don't appear to work any more

[sebbASF]

As the subject says:

infrastructure-website/README.md

Line 49 in 32874a8

## Preview PRs

[ML-dev-crypto]

I would like to work on this. I will correct the Markdown syntax for the "Preview PRs" heading in README.md to ensure it renders correctly.

[dave2wave]

In switching from buildbot based Pelican to GHA the preview feature may not be supported properly. It certainly requires an improved workflow and action. One clear spot is

https://github.com/apache/infrastructure-website/blob/master/.github/workflows/build-pelican.yml#L11