robin-hood-hashing: fix missing include

[planetmarshall]

Summary

Changes to recipe: robin-hood-hashing/3.11.5

Motivation

Build fails with GCC 15

Details

patch missing include

---

• Read the contributing guidelines
• Checked that this PR is not a duplicate: list of PRs by recipe
• Tested locally with at least one configuration using a recent version of Conan

[AbrilRBS]

Thanks a lot for providing this PR

I'm accepting this as the change is trivial and can not cause issues, but please note that this library is no longer maintained, and moving forward we will not be maintaing it

(Today it's a single header, but as new compilers are released, the code will get getting more "oudated" and we can't commit to support these kinds of fixes forever)

Note that as per the upstream deprecation notice, https://github.com/martinus/unordered_dense is the recommended replacement for this library from the same author, so it's possible that in the future we'll mark this as deprecated and point to the new recipe

[planetmarshall]

I'm accepting this as the change is trivial and can not cause issues, but please note that this library is no longer maintained, and moving forward we will not be maintaing it

It was vulkan-validationlayers that depended on this recipe. Looking at the sources for that package, they have deprecated it in favour of parallel-hashmap. I'll put a comment in #27460