Auto merge of #722 - AzureMarker:tweak/publish-using-ubuntu, r=jackh726

Switch runner for publish job to Ubuntu from Mac

Closes #721

I ran this on my repo to verify (note: it eventually fails because I didn't set it up with actual publishing keys, and I added in the fix from #720 so it wouldn't immediately fail):
https://github.com/AzureMarker/chalk/runs/3187634249

Note: Merge #720 first so the book lint check passes.

Author: bors

.github/workflows/publish.yml

@@ -7,7 +7,7 @@ on:
 jobs:
   publish:
     name: Publish
-    runs-on: macos-latest
+    runs-on: ubuntu-latest
 
     steps:
       - name: Checkout repository