Document Linux ARM64 support in README

[Copilot]

• Analyze the issue and understand the problem
• Review the build_binaries.yml workflow configuration
• Check the linux.bash build script
• Verify releases contain libscip-linux-arm.zip
• Update README documentation to clarify supported platforms
• Investigate root cause of missing ARM64 wheels in PySCIPOpt 5.7.0

Analysis Summary

After thorough investigation, I found that Linux ARM64 support IS properly implemented in this repository:

1. The build_binaries.yml workflow correctly includes the linux-arm-build-binaries job
2. The job uses ubuntu-24.04-arm runner with quay.io/pypa/manylinux_2_28_aarch64 container
3. The linux.bash script correctly handles ARM=ON environment variable
4. Recent releases (v0.8.0, v0.9.0, v0.10.0) all include libscip-linux-arm.zip assets

Root Cause

The actual issue is in PySCIPOpt's .github/workflows/build_wheels.yml - it does not include Linux ARM64 in its build matrix:

matrix:
  include:
    - os: ubuntu-22.04      # x86_64 only
      arch: x86_64
    - os: macos-14
      arch: arm64
    - os: macos-15-intel
      arch: x86_64
    - os: windows-latest
      arch: AMD64

Missing entry needed:

    - os: ubuntu-24.04-arm
      arch: aarch64

Changes Made

• Updated README.md to document all supported platforms including Linux ARM64
• Added a table showing platform support with corresponding artifact names
• Added usage documentation for release artifacts

Note: The fix for the missing Linux ARM64 wheels needs to be applied in the PySCIPOpt repository, not here.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Linux arm64 lost in 5.7.0 #1121</issue_title>
<issue_description>The support for manylinux_2_28_aarch64 introduced somewhere around scipopt/PySCIPOpt#1020 in version 5.6.0 apparently got lost again in version 5.7.0, see https://pypi.org/project/PySCIPOpt/5.7.0/#files.

Noticed by @gtjusila.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Linux arm64 lost in 5.7.0 #1121 #33

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[Joao-Dionisio]

No, support for Linux ARM64 was incorrectly dropped. It was lost somewhere around PySCIPOpt release 5.7.0 (roughly 2 weeks ago), you can see them here: https://github.com/scipopt/PySCIPOpt/releases

I want to bring back the support for Linux ARM64.

[Copilot]

No, support for Linux ARM64 was incorrectly dropped. It was lost somewhere around PySCIPOpt release 5.7.0 (roughly 2 weeks ago), you can see them here: https://github.com/scipopt/PySCIPOpt/releases

I...

I investigated further and found that the Linux ARM64 binaries (libscip-linux-arm.zip) are correctly being built and included in this repository's releases (v0.8.0+). The issue is that PySCIPOpt's build_wheels.yml workflow matrix doesn't include ubuntu-24.04-arm with aarch64 architecture - it only builds for ubuntu-22.04 with x86_64.

The fix needs to be made in the PySCIPOpt repository's .github/workflows/build_wheels.yml by adding a matrix entry like:

- os: ubuntu-24.04-arm
  arch: aarch64

Should I close this PR and file the issue/fix in the PySCIPOpt repository instead?