feat: add support for 26.05.x

[giovtorres]

This change adds support for Slurm 26.05.

[chriswasser]

cross-comment from #424: your new branch with commit 6242fad works on for my monitoring use cases on our cluster 👌

just two comments:

• You switched your versioning / branch name scheme to include the leading zero from SLURM's versioning (previously: 25.5.x for 25.05.x, now: 26.05.x for 26.05.x). Not a huge deal, but just wanted to mention this (potentially breaking) change as it might be worth to include in the CHANGELOG.
• In the future, I would love to see SLUID support within pyslurm since SLURM itself seems to have adapted these unique identifiers more thoroughly now. Compared to the previous JobIDs that could reset at some point (and even be reused for multiple restarts of the same job in case of node failures), SLUIDs finally offer a simple unique key for external database storage. Of course, this feature would not block the general release of pyslurm 26.05.x, but I just wanted to add something to the wishlist 😇

Thanks for providing an official 26.05.x compatible branch so quickly 🙏

[giovtorres]

Thank you for that callout. I renamed the branch to 26.5.x to match the existing pattern. I just ended up opening another PR: #427

[giovtorres]

Also, im not familiar with SLUID, but I’ll take a look and see. Thanks for suggesting!