[llvm] [Github] Make prune branches workflow save branch patches (PR #178539)

[via llvm-commits]

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@@ -27,4 +27,11 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: |
-          python3 .github/workflows/prune-unused-branches.py
+          mkdir patches
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cmtice wrote:

Should you add a flag to 'mkdir' so that it doesn't fail if the directory already exists?

https://github.com/llvm/llvm-project/pull/178539