build: remove wheel from explicit dependencies

It is a transitive dependency of setuptools. Since we gave up trying
to have deterministic build environments, it doesn't serve much value.
And it may make the lives of downstream packagers harder. So just remove
it.

Part of #207.

pyproject.toml

@@ -7,7 +7,6 @@ requires = [
     # workaround. See comment at
     # https://github.com/pypa/pip/issues/11859#issuecomment-2132287974.
     "setuptools<69.0.0",
-    "wheel>=0.41.2",
 ]
 # Need to use legacy backend because setup_zstd.py breaks build isolation.
 build-backend = "setuptools.build_meta:__legacy__"