chore: add separators between version sections changelog.md

[abdelhamid-f-nasser]

Description of the change

• Add horizontal separators between versions

Type of change

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

Related issues

• [MOB-13259] [CP] [FLT] Add horizontal separators between version release sections in CHANGELOG.md - JIRA

Checklists

Development

• [ ] Lint rules pass locally
• [ ] The code changed/added as part of this pull request has been covered with tests

Code review

• [ ] This pull request has a descriptive title and information useful to a reviewer
• [ ] Issue from task tracker has a link to this pull request

[InstabugCI]

Coverage Report

Label	Coverage	Status
Dart	85.8%	✅

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