docs: correct version floor in CHANGELOG 0.9.75 release notes

[detail-app]

The CHANGELOG entry for 0.9.75 incorrectly stated that the
SimpleBroker floor was raised to 4.2.0 and simplebroker-pg to 2.1.0.
Commit 3e04985 actually raised them to 4.3.0 and 2.2.0 respectively
to support the renamed insert_messages() API.

Introduced by commit 3e04985 (@VanL)

---

_{Doc Drift PRs can be configured here.}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.42%. Comparing base (d3ab41d) to head (8ad2b8b).

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #25      +/-   ##
==========================================
- Coverage   80.44%   80.42%   -0.03%     
==========================================
  Files         159      159              
  Lines       29600    29600              
==========================================
- Hits        23813    23806       -7     
- Misses       5787     5794       +7     

Flag	Coverage Δ
unittests	80.42% <ø> (-0.03%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.
see 6 files with indirect coverage changes

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update d3ab41d...8ad2b8b. Read the comment docs.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.