Add optional spec input to digger workflow

Add spec input for digger workflow with optional requirement.

Author: jocelo

.github/workflows/digger_workflow.yml

@@ -12,6 +12,9 @@ on:
         required: true
       run_name:
         required: false
+      spec:
+        description: 'spec input for digger'
+        required: false
 
 run-name: ${{ inputs.run_name}}