Update stackhpc-all-in-one.yml

Set runs-on to accept variables for when sharing workflow.

Author: MaxBed4d

.github/workflows/stackhpc-all-in-one.yml

@@ -86,7 +86,7 @@ jobs:
   all-in-one:
     name: All in one
     if: ${{ inputs.if && !cancelled() }}
-    runs-on: arc-skc-aio-runner
+    runs-on: [arc-skc-aio-runner, "${{ inputs.runner_var }}"]
     permissions: {}
     env:
       KAYOBE_ENVIRONMENT: ci-aio