Update the list of cached data files

[seisman]

The Tests workflow run show following messages, which means these files are not cached and are downloaded:

_________________ test_mercury_relief_01m_default_registration _________________
----------------------------- Captured stderr call -----------------------------
Notice:  [NOTICE]: Remote data courtesy of GMT data server oceania [http://oceania.generic-mapping-tools.org/]
Notice:  [NOTICE]: Messenger Mercury Relief at 01x01 arc minutes reduced by Gaussian Cartesian filtering (2 km fullwidth) [Becker et al., 2016].
Notice:  [NOTICE]:   -> Download 30x30 degree grid tile (mercury_relief_01m_g): N00W030
__________________ test_moon_relief_01m_default_registration ___________________
----------------------------- Captured stderr call -----------------------------
Notice:  [NOTICE]: Remote data courtesy of GMT data server oceania [http://oceania.generic-mapping-tools.org/]
Notice:  [NOTICE]: LOLA Moon Relief at 01x01 arc minutes reduced by Gaussian Cartesian filtering (1.4 km fullwidth) [Mazarico et al., 2013].
Notice:  [NOTICE]:   -> Download 30x30 degree grid tile (moon_relief_01m_g): N00W030
__________________ test_pluto_relief_01m_default_registration __________________
----------------------------- Captured stderr call -----------------------------
Notice:  [NOTICE]: Remote data courtesy of GMT data server oceania [http://oceania.generic-mapping-tools.org/]
Notice:  [NOTICE]: New Horizons Pluto Relief at 01x01 arc minutes reduced by Gaussian Cartesian filtering (1 km fullwidth) [Moore et al., 2016].
Notice:  [NOTICE]:   -> Download 30x30 degree grid tile (pluto_relief_01m_g): N00W030
___________________ test_dataset_to_strings_with_none_values ___________________
----------------------------- Captured stderr call -----------------------------
Notice:  [NOTICE]: Remote data courtesy of GMT data server oceania [http://oceania.generic-mapping-tools.org/]
Notice:  [NOTICE]: SRTM15 Earth Relief v2.5.5 original at 15x15 arc seconds [Tozer et al., 2019].
Notice:  [NOTICE]:   -> Download 10x10 degree grid tile (earth_relief_15s_p): N00E000

This PR fixes the issue.