fix: execute PR creation sequentially to avoid race conditions

Add max-parallel: 1 to matrix strategy to ensure PRs are created
and auto-merge is enabled one at a time, preventing "Base branch
was modified" errors when multiple updates are detected.

Author: SckyzO

.github/workflows/scan-updates.yml

@@ -83,6 +83,7 @@ jobs:
     timeout-minutes: 10
     strategy:
       fail-fast: false
+      max-parallel: 1
       matrix:
         exporter: ${{ fromJson(needs.detect-updates.outputs.updates) }}
     steps: