run 'Link Checker: All English' on ubuntu-20.04-xl (github#28574)

Author: peterbe

.github/workflows/link-check-all.yml

@@ -24,7 +24,7 @@ concurrency:
 
 jobs:
   check-links:
-    runs-on: ${{ fromJSON('["ubuntu-latest", "self-hosted"]')[github.repository == 'github/docs-internal'] }}
+    runs-on: ${{ fromJSON('["ubuntu-latest", "ubuntu-20.04-xl"]')[github.repository == 'github/docs-internal'] }}
     steps:
       - name: Checkout
         uses: actions/checkout@dcd71f646680f2efd8db4afa5ad64fdcba30e748