Run deployment action on Ubuntu

Author: jmroot

.github/workflows/main.yml

@@ -4,6 +4,7 @@ on:
   push:
     branches:
       - master
+      - linux-ci
 
 permissions:
   contents: read
@@ -13,7 +14,7 @@ jobs:
     name: Build and deploy www
     concurrency:
       group: www-${{ github.ref }}
-    runs-on: macos-latest
+    runs-on: ubuntu-latest
 
     steps:
       - name: Checkout macports-www