README: promo badge and a tip block for the sign-up code

Merged
AL
12d ago
+3-1

The sign-up line becomes a GitHub tip block and a badge goes into the badge row, so the GITHUB code is easier to spot. PyPI's renderer (readme_renderer 46) turns the tip block into an admonition as well.

šŸ¤– Generated with Claude Code


Summary by cubic

Highlights the free 2 GB sign-up promo in the README by adding a badge to the badge row and turning the sign-up line into a GitHub tip block. PyPI's renderer (readme_renderer 46) also renders the tip block as an admonition.