hooks/post_gen_project.py: Regression in replay file name handling

[claui]

This line in post_gen_project.py:

(PurePath(config_dict['replay_dir']) / template_name).with_suffix('.json')

results in the following replay value in manifest.json:

{
  "upstream": {
    "type": "cookiecutter-template",
    "source": "https://github.com/claui/cookiecutter-python-package.git",
    "commit": "3b551359fa471758aaf00f5ec2433634c67f29e3",
    "replay": "cookiecutter_replay/cookiecutter-python-package.git.json",
    "patches": [
      "patches/disable-install-step.patch"
    ],
    "nextPatches": [
      "patches/disable-install-step.patch"
    ]
  }
}

The superfluous .git must be removed.