fix: escape single quotes in changelog generation script

Update the command in the GitLab CI configuration to properly escape 
single quotes in the `sed` command for generating the CHANGELOG.md. This 
ensures that the command executes correctly in the CI environment, 
preventing potential syntax errors during the build process.

Release.gitlab-ci.yml

@@ -28,7 +28,7 @@ unbound_release_changelog:
   script:
   - 'echo "Generating changelog"'
   - 'git-cliff --bump --unreleased --strip header > CHANGES.md'
-  - 'git-cliff --bump | sed 's/\s\+$//' > CHANGELOG.md'
+  - 'git-cliff --bump | sed '\''s/\s\+$//'\'' > CHANGELOG.md'
   - 'echo "Bumping version"'
   - 'git-cliff --bumped-version 2>/dev/null > VERSION'
   artifacts: