As part of #528 cuvs's doc builds were modified to pull Breathe from pip. That was necessary because the nvidia-sphinx-theme requires Sphinx 8 but [the conda-forge Breathe package was not compatible with that Sphinx version](conda-forge/breathe-feedstock#63). I fixed that in conda-forge/breathe-feedstock#64, so now we can go back to using Breathe from conda to avoid mixing pip and conda for dependency management in the same environment.

Authors:
  - Vyas Ramasubramani (https://github.com/vyasr)

Approvers:
  - Bradley Dice (https://github.com/bdice)

URL: #554

**This is exactly the same set of changes already approved in #69.**

`cugraph-docs` was switched from private to public during the lifetime of that PR, which put CI into a state where that PR couldn't be merged: #69 (comment)

---

Development and the vision for this project has stabilized here quite a bit over the last few weeks, so I think it's a good time to simplify things.

This proposes the following:

* removing configuration for codecov
  - *(there are no tests running here)*
* removing patterns in CODEOWNERS that don't match any files
* removing anything related to CUDA 11, pyproject.toml, or requirements.txt in `dependencies.yaml` and related files
  - *this repo exclusively uses conda, and only a single major version of CUDA*
* updating to `sphinx>=8` and `breathe>=4.35`
  - *to match the rest of RAPIDS, e.g. rapidsai/cugraph#4839, rapidsai/cuvs#528
  - *floors also mean faster conda solves and fewer surprises at build time*
* removing unnecessary files in `ci/utils`
  - *these appear to have been copied from `cugraph`, but they're not needed as we don't do notebook testing here*

## Notes for Reviewers

### How I tested this

Tested the `update-version.sh` changes like this:

```shell
./ci/release/update-version.sh '25.04.00'

git grep -E '25\.2'
git grep -E '25\.02'
```

Authors:
  - James Lamb (https://github.com/jameslamb)

Approvers:
  - Don Acosta (https://github.com/acostadon)
  - Ray Douglass (https://github.com/raydouglass)
  - Bradley Dice (https://github.com/bdice)

URL: #71