Docs: update CUDA EP package guidance for CUDA 13 default (1.27+) and CUDA 12.8 legacy (#29781)
The CUDA Execution Provider docs were still centered on CUDA 12
defaults, which made it unclear which `onnxruntime-gpu`/NuGet GPU
packages map to CUDA 13-era releases. This updates the requirements
guidance to reflect the package baseline shift starting in 1.27.
- **Requirements baseline update**
- Updated CUDA minor-version compatibility text to explicitly cover CUDA
**12.8** and **13.0** package builds.
- Replaced the outdated “1.19 => CUDA 12 default” note with current
guidance:
- **1.27+** default GPU packages use **CUDA 13.0** (PyPI + NuGet)
- Older default GPU packages use **CUDA 12.8**
- **Version matrix coverage**
- Added a new **CUDA 13.x** section for ORT **1.27.x–1.29.x**.
- Added a **CUDA 12.8** row for ORT **1.21.x–1.26.x** in the CUDA 12.x
table.
- **Doc clarity for package selection**
- Clarifies how to choose package lines by CUDA major/minor expectations
across recent ORT releases.
```markdown
Note: Starting with version 1.27, GPU packages published to PyPI (`onnxruntime-gpu`) and NuGet (`Microsoft.ML.OnnxRuntime.Gpu`) are built with **CUDA 13.0** by default. Older GPU package versions are built with **CUDA 12.8** by default.
```
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Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>