Fixes tests fails because of the eof empty line mismatch at windows

[malaskowski]

Description

When running tests on Windows, sometimes unit tests failed because of a mismatch in the number of empty lines at the end of CHANGELOG.md or gradle.properties files.

Motivation and Context

Fixes https://github.com/Knotx/knotx-aggregator/issues/35

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• [x] I have read the CONTRIBUTING document.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.

---

I hereby agree to the terms of the Knot.x Contributor License Agreement.