Tune tolerance to fix test failures with PROJ 9.1.1.

[sebastic]

As reported in #484, test_area_def_geocentric_resolution fails with PROJ 9.1.1 because the tolerance is exceeded.

• [x] Closes #484
• [x] Tests passed
• [x] Passes git diff origin/main **/*py | flake8 --diff

[codecov[bot]]

Codecov Report

Merging #485 (0d97737) into main (790c847) will not change coverage. The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #485   +/-   ##
=======================================
  Coverage   94.32%   94.32%           
=======================================
  Files          74       74           
  Lines       12890    12890           
=======================================
  Hits        12159    12159           
  Misses        731      731           

Flag	Coverage Δ
unittests	94.32% <100.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
pyresample/test/test_geometry.py	99.54% <100.00%> (ø)

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[coveralls]

Coverage remained the same at 93.851% when pulling 0d977378a860e5260dcb9ac41582a0cc34e0c664 on sebastic:test_area_def_geocentric_resolution into 790c847bc3f418e6ddae641219e60f7e865e6719 on pytroll:main.