CI: Test NumPy 2.3 in the GMT Tests workflow (#3968)

Author: seisman

.github/workflows/ci_tests.yaml

@@ -78,7 +78,7 @@ jobs:
             optional-packages: ' contextily geopandas ipython pyarrow-core rioxarray netCDF4 sphinx-gallery'
           # Python 3.13 + core packages (latest versions) + optional packages
           - python-version: '3.13'
-            numpy-version: '2.2'
+            numpy-version: '2.3'
             pandas-version: ''
             xarray-version: ''
             optional-packages: ' contextily geopandas ipython pyarrow-core rioxarray netCDF4 sphinx-gallery'