[BUG] np.int deprecated with np 1.20

[Japhiolite]

Hello there, coding a bit in subsurface, I got an error in the tests that np.int is deprecated in newer numpy versions:

`np.int` was a deprecated alias for the builtin `int`. To avoid this error in existing code, use `int` by itself. Doing this will not modify any behavior and is safe. When replacing `np.int`, you may wish to use e.g. `np.int64` or `np.int32` to specify the precision. If you wish to review your current use, check the release note link for additional information.
The aliases was originally deprecated in NumPy 1.20; for more details and guidance see the original release note at:
https://numpy.org/devdocs/release/1.20.0-notes.html#deprecations

Following the recommendation, I simply changed the single occurence in striplog to int

Best Jan