Use ubuntu-latest in the publish-to-hex.yml workflow

Author: whatyouhide

.github/workflows/publish-to-hex.yml

@@ -12,7 +12,7 @@ jobs:
   publish:
     name: Publish to Hex
 
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
 
     steps:
       - name: Checkout this repository