Resolve warnings from pytest

[veenstrajelmer]

tests/conftest.py:12
  /home/runner/work/dfm_tools/dfm_tools/tests/conftest.py:12: PytestRemovedIn9Warning: Marks applied to fixtures have no effect
  See docs: https://docs.pytest.org/en/stable/deprecations.html#applying-a-mark-to-a-fixture-function
    @pytest.mark.requiressecrets

tests/test_coastlines.py: 8 warnings
tests/test_hydrolib_helpers.py: 3 warnings
tests/test_meshkernel_helpers.py: 7 warnings
  /home/runner/work/dfm_tools/dfm_tools/dfm_tools/coastlines.py:65: DeprecationWarning: The 'include_fields' and 'ignore_fields' keywords are deprecated, and will be removed in a future release. You can use the 'columns' keyword instead to select which columns to read.
    coastlines_gdb_L1 = gpd.read_file(file_shp_L1, include_fields=include_fields, where=f"area>{min_area}", bbox=bbox)

tests/test_coastlines.py: 8 warnings
tests/test_hydrolib_helpers.py: 3 warnings
tests/test_meshkernel_helpers.py: 7 warnings
  /home/runner/work/dfm_tools/dfm_tools/dfm_tools/coastlines.py:66: DeprecationWarning: The 'include_fields' and 'ignore_fields' keywords are deprecated, and will be removed in a future release. You can use the 'columns' keyword instead to select which columns to read.
    coastlines_gdb_L6 = gpd.read_file(file_shp_L6, include_fields=include_fields, where=f"area>{min_area}", bbox=bbox)

tests/test_coastlines.py::test_get_coastlines_gdb_global
tests/test_coastlines.py::test_get_coastlines_gdb_lakes_islandsinlakes
  /home/runner/work/dfm_tools/dfm_tools/dfm_tools/coastlines.py:69: DeprecationWarning: The 'include_fields' and 'ignore_fields' keywords are deprecated, and will be removed in a future release. You can use the 'columns' keyword instead to select which columns to read.
    coastlines_gdb_L2 = gpd.read_file(file_shp_L2, include_fields=include_fields, where=f"area>{min_area}", bbox=bbox)

tests/test_coastlines.py::test_get_coastlines_gdb_global
tests/test_coastlines.py::test_get_coastlines_gdb_lakes_islandsinlakes
  /home/runner/work/dfm_tools/dfm_tools/dfm_tools/coastlines.py:71: DeprecationWarning: The 'include_fields' and 'ignore_fields' keywords are deprecated, and will be removed in a future release. You can use the 'columns' keyword instead to select which columns to read.
    coastlines_gdb_L3 = gpd.read_file(file_shp_L3, include_fields=include_fields, where=f"area>{min_area}", bbox=bbox)

tests/test_observations.py::test_ssh_netcdf_overview
  /home/runner/work/dfm_tools/dfm_tools/dfm_tools/observations.py:1045: FutureWarning: 'H' is deprecated and will be removed in a future version, please use 'h' instead.
    time_hr_uniq = ds_slice.time.to_pandas().index.round("H").drop_duplicates()