Update CHANGES.rst

[stscieisenhamer]

This PR addresses a badly edited changelog for the uneven ramp fitting. This is NOT in the 1.4.2 release and should go into the unreleased section.

Checklist

• ~added entry in CHANGES.rst (either in Bug Fixes or Changes to API)~
• ~updated relevant tests~
• ~updated relevant documentation~
• [ ] updated relevant milestone(s)
• [ ] added relevant label(s)

[codecov[bot]]

Codecov Report

Patch has no changes to coverable lines.

:loudspeaker: Thoughts on this report? Let us know!.