Missing or extra line breaks in the Changelog unreleased section are retained in the new version-bumped section

[paulshryock]

When there are missing or extra line breaks in the Unreleased section, those missing or extra new lines are retained in the version-bumped section after running Release Bump. They should be added and removed automatically to fix formatting.

Acceptance criteria

1. Add missing new lines
   • GIVEN: There are missing new lines in the Unreleased section
   • WHEN: Release Bump is run
   • THEN: There are no missing new lines in the version-bumped section
2. Remove extra new lines
   • GIVEN: There are extra new lines in the Unreleased section
   • WHEN: Release Bump is run
   • THEN: There are no extra new lines in the version-bumped section

Example

This:

## Unreleased

### Added
- Add something.
### Changed
- Changed something.
- Changed something else.


### Removed
- Removed something.

- Removed something else.

### Deprecated
### Fixed

### Security

Should become:

## [<version>] - <date>

### Added
- Add something.

### Changed
- Changed something.
- Changed something else.

### Removed
- Removed something.
- Removed something else.

Instead of:

## [<version>] - <date>

### Added
- Add something.
### Changed
- Changed something.
- Changed something else.


### Removed
- Removed something.

- Removed something else.