helm chart publisher: use proper ref for checkout (#12392)

Author: valentijnscholten

.github/workflows/release-x-manual-helm-chart.yml

@@ -30,7 +30,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
-          ref: master
+          ref: ${{ inputs.release_number }}
           fetch-depth: 0
 
       # This action is deprecated. Not sure if it is even being used anymore...