docs: drop non-user-facing CI entry from 0.8.1 changelog

The 0.8.1 "### Added" entry documented an internal CI job, which is not a
user-facing change to the module's surface (functions, tasks, $PSBPreference,
or build/publish behavior). No prior release in this changelog documents CI,
test, or tooling changes — keep that convention. The entry was also stale:
the bespoke import-smoke job was replaced by the shared psake/.github ModuleCI
workflow's full 5.1 test run in #126. The user-facing "### Fixed" entry for the
5.1 import regression remains.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: tablackburn

CHANGELOG.md

@@ -20,13 +20,6 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
   Windows (matching the existing pattern in `Build-PSBuildUpdatableHelp`). Behavior
   on PowerShell 7+ is unchanged.
 
-### Added
-
-- An `Import smoke (Windows PowerShell 5.1)` CI job that parses and imports the
-  module on the real lowest-supported engine, so a construct that breaks import on
-  Windows PowerShell 5.1 (such as a PowerShell 7+-only ternary operator) fails CI
-  deterministically.
-
 ## [0.8.0] 2026-02-20
 
 ### Added