Correct host image promote github token

Author: MoteHue

.github/workflows/stackhpc-promote.yml

@@ -51,7 +51,7 @@ jobs:
           --repo stackhpc/stackhpc-kayobe-config \
           --ref $BRANCH_NAME
         env:
-          GITHUB_TOKEN: ${{ secrets.STACKHPC_RELEASE_TRAIN_TOKEN }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           BRANCH_NAME: ${{ github.head_ref || github.ref_name }}
 
       - name: Display link to overcloud host image promotion workflows