v4.0.0

• Breaking change: Drop support for Python 3.8, require Python >= 3.9
• Breaking change: Remove deprecated xxhash.VERSION_TUPLE
• Breaking change: The input keyword argument is renamed to data
  across constructors, update(), and one-shot functions
• Breaking change: str input is no longer accepted and raises
  TypeError: Strings must be encoded before hashing; encode to
  bytes before hashing
• Upgrade xxHash from v0.8.2 to v0.8.3. Note: on GCC/Clang source builds
  that target AVX2 (e.g. -march=x86-64-v3), upstream v0.8.3
  autovectorizes XXH64_update() and makes the xxh64 streaming path
  about 2x slower. The shipped wheels are built for baseline x86-64 and
  are unaffected. Source builds can work around it by adding
  -fno-tree-vectorize to the compiler flags.
• Add per-object locking for thread safety, with sub-interpreter and
  free-threaded (no-GIL) Python support
• Speed up hash constructors by switching them to tp_vectorcall.
• Build pyodide wasm32 wheels
• Add s390x big-endian test job
• Add Python 3.15 classifier
• CI: shard the PyPI upload into parallel groups and create the GitHub
  Release automatically