Unpkg link is broken

[davestewart]

Bug

The unpkg link is not working in the docs:

• https://spectre-org.github.io/spectre-docs/docs/introduction/installation.html
• https://unpkg.com/@spectre-org/spectre-css/dist/spectre.min.css

Fix

• dry run publish the package, and review the unpkg link

[davestewart]

Looks like this was only because unpkg was down