docs(deps): simplify the managing-dependencies skill

[WilliamBergamin]

Summary

Simplifies the managing-dependencies skill.

What changed:

• No repo facts in the skill. It says where to read them instead (pyproject.toml, a grep over workflows and scripts), so it can't go stale.
• Examples use a fictional pkg.
• Adds what was missing: 3+ way splits, splitting only the Pythons the bumped line covers, and Dependabot rewriting only the last line of a split section.
• New one-Python bands use == "3.9". python_version is major.minor, so that covers every 3.9 patch. Existing lines are left alone.
• Shorter: 121 to 81 lines.

Testing

n/a

Category

• slack_sdk.web.WebClient (sync/async) (Web API client)
• slack_sdk.webhook.WebhookClient (sync/async) (Incoming Webhook, response_url sender)
• slack_sdk.socket_mode (Socket Mode client)
• slack_sdk.signature (Request Signature Verifier)
• slack_sdk.oauth (OAuth Flow Utilities)
• slack_sdk.models (UI component builders)
• slack_sdk.scim (SCIM API client)
• slack_sdk.audit_logs (Audit Logs API client)
• slack_sdk.rtm_v2 (RTM client)
• /docs (Documents)
• /tutorial (PythOnBoardingBot tutorial)
• tests/integration_tests (Automated tests for this library)

Requirements

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.
• I've run python3 -m venv .venv && source .venv/bin/activate && ./scripts/run_validation.sh after making the changes. (Markdown only, so I'm relying on CI.)

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.15%. Comparing base (2bc474a) to head (8042d94).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1972      +/-   ##
==========================================
- Coverage   84.16%   84.15%   -0.01%     
==========================================
  Files         118      118              
  Lines       13569    13569              
==========================================
- Hits        11420    11419       -1     
- Misses       2149     2150       +1     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.