Update transaction to 2.1.1

[pyup-bot]

There's a new version of transaction available.
You are currently using 2.1.0. I have updated it to 2.1.1

These links might come in handy: PyPI | Changelog | Repo

Changelog

2.1.1

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• For backward compatibility, relax the requirements that transaction
  meta data (user or description) be text:

• If None is assigned, the assignment is ignored.

• If a non-text value is assigned, a warning is issued and the value
  is converted to text. If the value is a binary string, it will be
  decoded with the UTF-8 encoding the replace error policy.

Got merge conflicts? Close this PR and delete the branch. I'll create a new PR for you.

Happy merging! 🤖