Add subset contributor-tenure collector and manual workflow from release-note RSTs

[Copilot]

Adds a focused validation path for collecting contributor tenure data from a subset of SciPy releases. The change introduces a standalone collector plus a manual GitHub Actions workflow that runs it, captures logs, and publishes the generated outputs.

• Collector script

  • Adds collect_scipy_contributors_subset.py
  • Reads the repository’s canonical release-note RST sources under doc/source/release
  • Parses the requested subset releases: 0.8.0, 1.0.0, 1.7.0, 1.11.0, 1.17.0, 1.18.0
  • Emits scipy_contributor_tenure_subset.csv with:
    • release
    • year
    • person_raw
    • is_first_time_marker
    • first_seen_release
    • tenure_release_index

• Workflow

  • Adds .github/workflows/scipy_contributors_subset.yml
  • Supports workflow_dispatch
  • Installs the requested Python deps (requests, beautifulsoup4)
  • Runs the collector, saves console output to subset_run_output.txt, and uploads both output files as artifacts

• Checked-in outputs

  • Commits:
    • scipy_contributor_tenure_subset.csv
    • subset_run_output.txt
  • Current parsed counts from the RST originals:
    • 0.8.0: 0
    • 1.0.0: 121
    • 1.7.0: 126
    • 1.11.0: 134
    • 1.17.0: 117
    • 1.18.0: 0

• Observed gaps in source data

  • 0.8.0: no parseable Authors entries in the RST
  • 1.18.0: Authors section exists but is empty in the RST
  • No workflow run link/name is included here because the manual workflow was added but not triggered from this environment

- name: Run contributor subset collector
  run: |
    python collect_scipy_contributors_subset.py | tee subset_run_output.txt