heyoka 7.6.0

[bluescarni]

This new heyoka release focuses on supporting the recently-released LLVM 21. At the same time, support for LLVM<17 has been removed.

As a minor feature addition, it is now possible to specify an alternative origin when downloading the latest IERS EOP data. This should improve resiliency in case of transient network issues.

As usual, the full changelog is available here:

https://bluescarni.github.io/heyoka/changelog.html

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This discussion was created from the release heyoka 7.6.0.