Depend on audeer>=1.18.0

[hagenw]

This tests the code for audeer>=2.0.0 and updates the code.
It turns out that there are no needed changes for audeer>=2.0.0 and we can instead update to audeer>=1.18.0 and audeer>=1.21.0 for the tests.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (28a2f59) 100.0% compared to head (9e11141) 100.0%.
Report is 1 commits behind head on main.

Additional details and impacted files

Files	Coverage Δ
audinterface/core/feature.py	100.0% <100.0%> (ø)
audinterface/core/process.py	100.0% <100.0%> (ø)
audinterface/core/segment.py	100.0% <100.0%> (ø)
audinterface/core/utils.py	100.0% <100.0%> (ø)