PyTorch 2.1.0

Verified 2026-08, with a caveat: one automated pull of PyTorch's official previous-versions page returned CUDA 13.0/13.2 and ROCm 7.2 for this entry — those TLDs didn't exist until 2026 and cannot be correct for a package released in October 2023 (pytorch.org's previous-versions page appears to get its install-command index rewritten over time to whatever wheels are still hosted, rather than staying a fixed historical record). Discarded that anomalous data rather than publish it; CUDA 11.8/12.1 and ROCm 5.6 used instead, cross-referenced against the surrounding 2.0.x/2.1.1 entries' progression and PyTorch's own 2.1.0 release notes. Added to fix dead cross-links: ROCm 5.7.0's page listed this version as a compatible build before this entry existed.