✨ Add automatic changelog generation

[rubenaeg]

Proposed changes

This PR adds a GitHub Workflow, in addition to some scripts for automatic changelog generation.
The workflow is triggered on PR Merge and Tag Creation, which will be triggered by a lerna publish by executing the postpublish script. This script pushes the latest tags for each package to origin and remote and then checks for the workflow status to pull changes (i.e. newly generated changelogs) to the local repository.

Also fixes #179

Types of changes

• 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 change)

Checklist

• My code follows the code style of this project
• My change requires a change to the documentation
• I have updated the documentation accordingly
• I have added tests to cover my changes
• All new and existing tests passed