Log Message:
xxhash: updated to 0.8.1

v0.8.1
- perf : much improved performance for XXH3 streaming variants, notably on gcc \ 
and msvc
- perf : improved XXH64 speed and latency on small inputs
- perf : small XXH32 speed and latency improvement on small inputs of random size
- perf : minor stack usage improvement for XXH32 and XXH64
- api  : new experimental variants XXH3_*_withSecretandSeed()
- api  : update XXH3_generateSecret(), can no generate secret of any size (>= \ 
XXH3_SECRET_SIZE_MIN)
- cli  : xxhsum can now generate and check XXH3 checksums, using command `-H3`
- build: can build xxhash without XXH3, with new build macro XXH_NO_XXH3
- build: fix xxh_x86dispatch build with MSVC, by @apankrat
- build: XXH_INLINE_ALL can always be used safely, even after XXH_NAMESPACE or a \ 
previous XXH_INLINE_ALL
- build: improved PPC64LE vector support, by @mpe
- install: fix pkgconfig, by @ellert
- install: compatibility with Haiku, by @Begasus
- doc  : code comments made compatible with doxygen, by @easyaspi314
- misc : XXH_ACCEPT_NULL_INPUT_POINTER is no longer necessary, all functions can \ 
accept NULL input pointers, as long as size == 0
- misc : complete refactor of CI tests on Github Actions, offering much larger \ 
coverage, by @t-mat
- misc : xxhsum code base split into multiple specialized units, within \ 
directory cli/, by @easyaspi314