check-run: use a reasonable default for details-url

The details URL should in almost all cases point to the current workflow
run. So let's do that by default!

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

check-run/action.yml

@@ -34,7 +34,7 @@ inputs:
     default: ''
   details-url:
     description: 'The details URL of the Check Run (required when creating a new one)'
-    default: ''
+    default: '${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}'
   conclusion:
     description: 'If set, the Check Run will be marked as completed'
     default: ''