Resolve "Manually check dependencies for updates"

Summary

All dependencies are updated within their pinned versions.

Version constraints for NumPy, pandas, wetterdienst and mypy have been updated. The new pandas version introduces some new deprecations, as seen below.

Please list breaking changes, new features or bugfixes

• Breaking changes:
  • Updated numpy from 1.24.0 to 1.26.0
  • Updated pandas from 2.0.3 to 2.2.2
    • The new pandas version introduces some new deprecations:
      • using ffill() instead of fillna(method="ffill")
      • resampling a dataframe with a lowercase s instead of uppercase S for seconds
      • indexing a dataframe with d.iloc(i) instead of d[i] with integers
  • Updated wetterdienst from 0.72.0 to 0.81.0
  • Updated mypy from 1.5 to 1.9
• New features:
• Bugfixes:
  • Resolved pandas deprecations by updating to recommended methods.

Closes #209