[BUG]: Fix interpolation scheme for native parcellation and mask

[synchon]

• [x] description of feature/fix
• [x] tests added/passed
• [x] add an entry for the latest changes

This PR fixes the interpolation scheme for parcellation and mask transformation to native space, to nearest neighbour instead of spline.

[github-actions[bot]]

PR Preview Action v1.4.4 :---: Preview removed because the pull request was closed. 2023-11-17 15:09 UTC

[codecov[bot]]

Codecov Report

Merging #276 (422f72c) into main (df4cee7) will not change coverage. The diff coverage is n/a.

Additional details and impacted files

[](https://app.codecov.io/gh/juaml/junifer/pull/276?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=juaml) ```diff @@ Coverage Diff @@ ## main #276 +/- ## ======================================= Coverage 89.81% 89.81% ======================================= Files 99 99 Lines 4371 4371 Branches 842 842 ======================================= Hits 3926 3926 Misses 305 305 Partials 140 140 ``` | [Flag](https://app.codecov.io/gh/juaml/junifer/pull/276/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=juaml) | Coverage Δ | | |---|---|---| | [docs](https://app.codecov.io/gh/juaml/junifer/pull/276/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=juaml) | `100.00% <ø> (ø)` | | | [junifer](https://app.codecov.io/gh/juaml/junifer/pull/276/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=juaml) | `89.81% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=juaml#carryforward-flags-in-the-pull-request-comment) to find out more. | [Files](https://app.codecov.io/gh/juaml/junifer/pull/276?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=juaml) | Coverage Δ | | |---|---|---| | [junifer/data/masks.py](https://app.codecov.io/gh/juaml/junifer/pull/276?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=juaml#diff-anVuaWZlci9kYXRhL21hc2tzLnB5) | `82.73% <ø> (ø)` | | | [junifer/data/parcellations.py](https://app.codecov.io/gh/juaml/junifer/pull/276?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=juaml#diff-anVuaWZlci9kYXRhL3BhcmNlbGxhdGlvbnMucHk=) | `88.59% <ø> (ø)` | |