CI use benchopt info --version to gate tests on min_benchopt_version

[tomMoral]

Problem

The compatibility gate compared versions with a bash lexicographic test:

if [[ "$benchopt_version" < "$min_version" ]]

< in [[ ]] is a string comparison, so once benchopt reaches 1.10.0 it is (wrongly) treated as older than 1.2–1.9. Because the Test step is guarded by if: compatible == 'true', every benchmark pinning one of those min_benchopt_version values would silently skip its tests (green, not red) under benchopt 1.10.0.

Change

Delegate the comparison to benchopt itself via the new benchopt info <benchmark> --version (benchopt/benchopt#1009), which exits non-zero when the installed benchopt is too old:

if [[ "$BENCHOPT_VERSION" == "git" ]] \
   || ! benchopt info --help | grep -q -- '--version' \
   || benchopt info ${{ inputs.benchmark_dir }} --version
then
  echo "compatible=true" >> $GITHUB_OUTPUT
else
  echo "compatible=false" >> $GITHUB_OUTPUT
fi

• git (dev) builds: always compatible, as before.
• The ! benchopt info --help | grep -q -- '--version' clause makes benchopt < 1.10.0 (which lacks the flag) fall through to compatible=true, so the test runs rather than being silently skipped.
• Otherwise the exit code of benchopt info --version decides.

Merge after benchopt 1.10.0 is on PyPI — the latest job needs the new flag. The default matrix (latest + git) is covered; the fall-through handles any benchmark pinning an older benchopt.

Depends on benchopt/benchopt#1009.