FIx inputs definitions.

Author: hellska

.github/workflows/dss-image-build.yaml

@@ -6,12 +6,15 @@ on:
   workflow_call:
     inputs:
       branch:
+        type: string
         description: "Branch to check for existence (e.g., 'upstream/b-open')"
         required: true
       chart-repo:
+        type: string
         description: "GitHub repository in 'owner/repo' format (e.g., 'ecmwf/dss-broker-chart')"
         required: true
       image_name:
+        type: string
         description: "Name of the Docker image to build (e.g., 'broker')"
         required: true
       repositories: