Prepare 2.6.0 release

[rly]

Prepare for release of PyNWB 2.6.0

Before merging:

• Major and minor releases: Update package versions in requirements.txt, requirements-dev.txt,
  requirements-doc.txt, requirements-opt.txt, and environment-ros3.yml to the latest versions,
  and update dependency ranges in pyproject.toml and minimums in requirements-min.txt as needed
• Check legal file dates and information in Legal.txt, license.txt, README.rst, docs/source/conf.py,
  and any other locations as needed
• Update setup.py as needed
• Update README.rst as needed
• Update src/pynwb/nwb-schema submodule as needed. Check the version number and commit SHA manually
• Update changelog (set release date) in CHANGELOG.md and any other docs as needed
• Run tests locally including gallery, validation, and streaming tests, and inspect all warnings and outputs
  (python test.py -v -p -i -b -w -r > out.txt 2>&1)
• Test docs locally and inspect all warnings and outputs cd docs; make clean && make html
• Push changes to this PR and make sure all PRs to be included in this release have been merged
• Check that the readthedocs build for this PR succeeds (build latest to pull the new branch, then activate and
  build docs for new branch): https://readthedocs.org/projects/pynwb/builds/

After merging:

1. Create release by following steps in docs/source/make_a_release.rst or use alias git pypi-release [tag] if set up
2. After the CI bot creates the new release (wait ~10 min), update the release notes on the
   GitHub releases page with the changelog
3. Check that the readthedocs "latest" and "stable" builds run and succeed
4. Update conda-forge/pynwb-feedstock with the latest version number
   and SHA256 retrieved from PyPI > PyNWB > Download Files > View hashes for the .tar.gz file. Re-render as needed

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (5d0e98d) 91.99% compared to head (8437326) 91.99%.

Additional details and impacted files

@@           Coverage Diff           @@
##              dev    #1779   +/-   ##
=======================================
  Coverage   91.99%   91.99%           
=======================================
  Files          27       27           
  Lines        2623     2623           
  Branches      685      685           
=======================================
  Hits         2413     2413           
  Misses        138      138           
  Partials       72       72           

Flag	Coverage Δ
integration	71.02% <ø> (ø)
unit	84.59% <ø> (ø)

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[rly]

This PR is now outdated