Update link to Prior Art labelmake to actively developed pdfme

[jch]

What?

Update README "Prior Art" labelmake item to active project. From labelmake README:

labelmake has now stopped development. Please use pdfme. pdfme is a renewed version of labelmake which allows to use template designers as a UI library, improved documentation, etc. Of course, open source and MIT licensed.

https://github.com/hand-dot/labelmake

Why?

Update doc

How?

n/a

Testing?

n/a

New Dependencies?

n/a

Screenshots

n/a

Suggested Reading?

n/a

Anything Else?

n/a

Checklist

• I read CONTRIBUTING.md.
• I read MAINTAINERSHIP.md#pull-requests.
• I added/updated unit tests for my changes.
• I added/updated integration tests for my changes.
• I ran the integration tests.
• I tested my changes in Node, Deno, and the browser.
• I viewed documents produced with my changes in Adobe Acrobat, Foxit Reader, Firefox, and Chrome.
• I added/updated doc comments for any new/modified public APIs.
• My changes work for both new and existing PDF files.
• I ran the linter on my changes.