ci/github-script/prepare: load systems

(cherry picked from commit 9caf455441)

.github/workflows/pr.yml

@@ -27,7 +27,7 @@ jobs:
       headBranch: ${{ steps.branches.outputs.head }}
       mergedSha: ${{ steps.prepare.outputs.mergedSha }}
       targetSha: ${{ steps.prepare.outputs.targetSha }}
-      systems: ${{ steps.systems.outputs.systems }}
+      systems: ${{ steps.prepare.outputs.systems }}
       touched: ${{ steps.files.outputs.touched }}
     steps:
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
@@ -44,11 +44,6 @@ jobs:
               core,
             })
 
-      - name: Load supported systems
-        id: systems
-        run: |
-          echo "systems=$(jq -c <ci/supportedSystems.json)" >> "$GITHUB_OUTPUT"
-
       - name: Determine branch type
         id: branches
         uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1

ci/github-script/prepare.js

@@ -49,6 +49,9 @@ module.exports = async ({ github, context, core }) => {
     )
     core.setOutput('mergedSha', mergedSha)
     core.setOutput('targetSha', targetSha)
+
+    core.setOutput('systems', require('../supportedSystems.json'))
+
     return
   }
   throw new Error(