Update test data key to 'tractograms.zip' instead of 'atlas.zip'

[elyz081]

Quick description

The test was failing due to fetching the wrong dataset ('atlas.zip') instead of the intended 'tractograms.zip'. I updated the fetch_data key to fetch 'tractograms.zip' instead of 'atlas.zip'.

Type of change

Check the relevant options.

• [x] 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 not work as expected)
• [ ] This change requires a documentation update

Provide data, screenshots, command line to test (if relevant)

Checklist

• [ ] My code follows the style guidelines of this project (run autopep8)
• [ ] I added relevant citations to scripts, modules and functions docstrings and descriptions
• [ ] I have performed a self-review of my code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [ ] My changes generate no new warnings
• [ ] I moved all functions from the script file (except the argparser and main) to scilpy modules
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] New and existing unit tests pass locally with my changes

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 94.56522% with 5 lines in your changes missing coverage. Please review.

Project coverage is 68.73%. Comparing base (460dac8) to head (343f7fe). Report is 36 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1024 +/- ## ========================================== + Coverage 68.61% 68.73% +0.11% ========================================== Files 426 430 +4 Lines 21835 22276 +441 Branches 3267 3327 +60 ========================================== + Hits 14982 15311 +329 - Misses 5578 5678 +100 - Partials 1275 1287 +12 ``` | [Components](https://app.codecov.io/gh/scilus/scilpy/pull/1024/components?src=pr&el=components&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=scilus) | Coverage Δ | | |---|---|---| | [Scripts](https://app.codecov.io/gh/scilus/scilpy/pull/1024/components?src=pr&el=component&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=scilus) | `69.62% <92.42%> (-0.31%)` | :arrow_down: | | [Library](https://app.codecov.io/gh/scilus/scilpy/pull/1024/components?src=pr&el=component&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=scilus) | `67.47% <100.00%> (+0.76%)` | :arrow_up: |

[frheault]

It seems like you created a branch from another branch (antoine's) instead of going back to master before creating it.

You can see a fee of Antoine's commit before yours., it should only be a single commit. Proposed solution: Close this PR, create a branch (from master), and redo the change, commit+push.

[frheault]

@arnaudbore It seems like the error is unrelated to the PR, am I crazy?

(Sorry about closing and opening, misclicked)