Update locate returned data type from np.int to np.int_

[fspinna]

This commit updates the data type from np.int to np.int_ in locate method of LearningShapelets. The change ensures compatibility with the NumPy library given that using the aliases of builtin types like np.int is deprecated.

[codecov-commenter]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (d8c1930) 94.57% compared to head (a7102c8) 94.57%.

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #453 +/- ## ======================================= Coverage 94.57% 94.57% ======================================= Files 62 62 Lines 4738 4738 ======================================= Hits 4481 4481 Misses 257 257 ``` | [Impacted Files](https://app.codecov.io/gh/tslearn-team/tslearn/pull/453?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=tslearn-team) | Coverage Δ | | |---|---|---| | [tslearn/shapelets/shapelets.py](https://app.codecov.io/gh/tslearn-team/tslearn/pull/453?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=tslearn-team#diff-dHNsZWFybi9zaGFwZWxldHMvc2hhcGVsZXRzLnB5) | `95.93% <100.00%> (ø)` | |

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[YannCabanes]

Hello @fspinna, thank you for your PR! Indeed, np.int is deprecated since NumPy 1.20.0: https://numpy.org/devdocs/release/1.20.0-notes.html It is replaced by np.int_ or int.