Bump ruff to 0.15.5 and ignore a violation

[seisman]

ruff v0.15.0 finds a new violation:

ruff check pygmt doc/conf.py examples
PERF102 When using only the values of a dict use the `values()` method
    --> pygmt/clib/session.py:1921:52
     |
1919 |                     # Dictionary, pandas.DataFrame or xarray.Dataset types.
1920 |                     # pandas.Series will be handled below like a 1-D numpy.ndarray.
1921 |                     _data = [array for _, array in data.items()]
     |                                                    ^^^^^^^^^^
1922 |                 else:
1923 |                     # Python list, tuple, numpy.ndarray, and pandas.Series types
     |
help: Replace `.items()` with `.values()`

but here, data can be a dict, panda.DataFrame or xarray.Dataset, so we can't change it to data.values().

This PR ignores the violation and bumps ruff to v0.15.0