Migrated CI from Azure Pipelines to GitHub Actions.
Until the release process is figured out in Actions, we'll stick to using Azure pipelines for releases.
Git branches can become very long (e.g. gitlab auto-generated branch
names), thus it would be nice to be able to truncate them to keep your
prompt lenght in line.
This patch adds two new options to the git_branch module:
* truncation_length: The amount of graphemes to of a gitbranch to
truncate to
* truncation_symbol: The symbol that should be used to indicate that a
branch name was trunctated
To be able to correctly work with UTF-8 graphemes, unicode-segmentation
was added as a dependency.