Update cookiecutter version

[Zeitsperre]

Pull Request Checklist:

• This PR addresses an already opened issue (for bug fixes / features)
  • This PR fixes #xyz
• (If applicable) Documentation has been added / updated (for bug fixes / features).
• (If applicable) Tests have been added.
• This PR does not seem to break the templates.
• CHANGELOG.rst has been updated (with summary of main changes).
  • Link to issue (:issue:number) and pull request (:pull:number) has been added.

What kind of change does this PR introduce?

• Updated to the latest cookiecutter template version.
• Addressed a few issues with existing workflows (security).

Does this PR introduce a breaking change?

Somewhat:

• New vulture pre-commit hook is now enabled. Warnings will now be emitted for dead code blocks.

Other information:

mypy will take some effort to adopt. Several underlying libraries need to be ignored in the configuration. Plenty of work is needed in xclim before this can be fully consistent for both libraries.

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