fix: pin miniforge to working version 25.9.1

[dlaehnemann]

Basically, this is only until this problem's fix is released in conda-libmamba-solver, probably via the miniforge installer: conda/constructor#1135

The issue that I am seeing, which this pinning should solve, is this error upon trying to re-install miniforge a second time during a GitHub Action run:

Running installer...
  /usr/bin/bash /home/runner/work/_temp/8b4dfb06-0e2d-4654-a587-7651f953ce7f.sh -f -b -p /home/runner/miniconda3
  PREFIX=/home/runner/miniconda3
  Unpacking bootstrapper...
  Warning: ln: failed to create symbolic link '/home/runner/miniconda3/_conda': File exists
  
  ln: failed to create symbolic link '/home/runner/miniconda3/_conda': File exists
Error: The process '/usr/bin/bash' failed with exit code 1

Summary by CodeRabbit

• Chores
  • Pinned the conda setup to a specific stable version (temporarily) to improve build reliability; added an inline TODO noting this is a temporary measure and referencing a known issue.

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[coderabbitai]

📝 Walkthrough

Walkthrough

Replaced miniforge-version: latest with pinned 25.9.1-0 in the Setup conda step of action.yml and added a TODO comment referencing a known issue; no other behavior or control-flow changes.

Changes

Cohort / File(s)	Summary
Version pinning action.yml	Replaced miniforge-version: latest with pinned 25.9.1-0 and added a TODO comment explaining the temporary rationale and referencing a known issue.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

Pre-merge checks and finishing touches

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The pull request title directly and accurately summarizes the main change: pinning miniforge to version 25.9.1 to fix a reinstall failure issue.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch fix/pin-miniforge-to-working-v25-9-1

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• action.yml (1 hunks)

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[coderabbitai]

Actionable comments posted: 1

📜 Review details

Configuration used: CodeRabbit UI

Review profile: CHILL

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Reviewing files that changed from the base of the PR and between 73be4c1 and 73a2973.

📒 Files selected for processing (1)

• action.yml (1 hunks)

[dlaehnemann]

I converted this to a draft, for now, as a rebuild of the conda-forge recipe for miniforge is already happening:
conda-forge/miniforge#838

If this fixes it, I'll close this pull request and delete it. If it doesn't, I'll investigate further.

[m-jahn]

if this get's fixed upstream, we don't need to bother about fixing it in other ways anymore. @dlaehnemann we had already a test PR + discussion going at #47 #48

[dlaehnemann]

Ah, thanks for the pointer. This is the one place where I didn't explicitly search for any discussion of this issue, even though I obviously should have.

[m-jahn]

Hi David, the issue persists even after merging the upstream PR, but that's no wonder because the current conda release 25.11.0 is the same as before. Do you know how often conda gets a new release? Maybe we do merge this PR for now until a new conda version is released.

[dlaehnemann]

OK, with regard to our discussion in the other issue, I updated the code comment in this pull request and this is ready for review.