Fixed a half-pixel shift in affine transformation

[konstntokas]

• Bug fix in affine transformations.
  Fixed a half-pixel shift that occurred in xcube_resampling.affine_transform_dataset
  and xcube_resampling.resample_in_space when the source and target grid mappings
  shared the same CRS and were regular.

Little example

We create a coarse small dataset:

Now, we interpolate this dataset to a fine grid (affine transformation)

Old verson:

With the changes in this PR:

new_version.ipynb
old_version.ipynb

Checklist:

• Add unit tests and/or doctests in docstrings
• Add docstrings and API docs for any new/modified user-facing classes and functions
• New/modified features documented in docs/
• Changes documented in CHANGES.md
• CI checks pass
• Test coverage remains or increases (target 100%)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.85%. Comparing base (c429669) to head (edcee1b).
⚠️ Report is 8 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #20   +/-   ##
=======================================
  Coverage   98.85%   98.85%           
=======================================
  Files          22       22           
  Lines        2182     2183    +1     
=======================================
+ Hits         2157     2158    +1     
  Misses         25       25           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[b-yogesh]

LGTM. Please look at my questions. Also, please change the title of this PR.