PQClean: Update to latest master

[RW-sec]

Hi Thom, this PR updates PQClean to latest master and makes the needed changes to the Rust wrappers. Please find below a short list of changes.

• Add NTRU Prime schemes
• Change Crystals-Dilithium4 to Crystals-Dilithium5
• Disable doc-tests for RainbowV because of stack overflow
• Update HQC to newest schemes
• Disable AVX2 implementation of HQC-RMRS-256 as there is a bug in "compute_syndromes()" in reed_solomon.c
• Sort the scheme variants alphabetically in implementations.yaml

This PR also fixes issue #17 as I have added a note to the implementations.yaml. I have also added the compiler flag carry-less multiplication "pclmul" and "sse2" to the AVX2 config for HQC compilation. Should we summarize all compiler flags under AVX2 or should we create a separate flag for SSE2 and pclmul?

[thomwiggers]

Thanks for the update by the way, I've been neglecting these crates.

[RW-sec]

Hi Thom, thank you for your feedback. I updated CHANGELOG.md and increased the version numbers. Please check if they are as expected. The report for the bug is on its way. I have to thank you for providing this project.

[RW-sec]

I applied your changes and built and tested it with cargo.

[thomwiggers]

I'm running the release script now.

[RW-sec]

Great. I am looking forward for further updates. It was a pleasure to make this PR.