Autoupdater insert changelog subsection after two empty lines

Summary

After updating project which does not contain new changes in CHANGELOG after Unreleased section it inserts subsection Changed after two blank lines.

Steps to reproduce

Run update command on project with empty Unreleased section

Expected behavior

Subsection Changed should be insert after Unreleased section without emty lines between them.

Actual behavior

There are two empty lines which should not exist.

Relevant logs and/or screenshots

Possible fixes

Change code in Changelog clas in markdown module.