Bump humanize to work-around https://github.com/pypa/setuptools/issues/4519

[benbz]

We're seeing installation of the S3 storage provider fail with the following when using a recent pip/setuptools:

Collecting humanize<0.6,>=0.5.1 (from synapse-s3-storage-provider==1.4.0)
  Downloading humanize-0.5.1.tar.gz (14 kB)
  Preparing metadata (setup.py): started
  Preparing metadata (setup.py): finished with status 'error'
  error: subprocess-exited-with-error
  
  × python setup.py egg_info did not run successfully.
  │ exit code: 1
  ╰─> [39 lines of output]
      /usr/local/lib/python3.11/site-packages/setuptools/dist.py:447: SetuptoolsDeprecationWarning: Invalid dash-separated options
      !!
      
              ********************************************************************************
              Usage of dash-separated 'upload-dir' will not be supported in future
              versions. Please use the underscore name 'upload_dir' instead.
      
              By 2024-Sep-26, you need to update your project and remove deprecated calls
              or your builds will no longer be supported.
      
              See https://setuptools.pypa.io/en/latest/userguide/declarative_config.html for details.
              ********************************************************************************
      
      !!
        opt = self.warn_dash_deprecation(opt, section)
      Traceback (most recent call last):
        File "<string>", line 2, in <module>
        File "<pip-setuptools-caller>", line 34, in <module>
        File "/tmp/pip-install-a7crpkz6/humanize_3ef5a456510341f0ae52d55ae1140165/setup.py", line 15, in <module>
          setup(
        File "/usr/local/lib/python3.11/site-packages/setuptools/__init__.py", line 108, in setup
          return distutils.core.setup(**attrs)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/usr/local/lib/python3.11/site-packages/setuptools/_distutils/core.py", line 146, in setup
          _setup_distribution = dist = klass(attrs)
                                       ^^^^^^^^^^^^
        File "/usr/local/lib/python3.11/site-packages/setuptools/dist.py", line 278, in __init__
          _Distribution.__init__(self, dist_attrs)
        File "/usr/local/lib/python3.11/site-packages/setuptools/_distutils/dist.py", line 286, in __init__
          self.finalize_options()
        File "/usr/local/lib/python3.11/site-packages/setuptools/dist.py", line 630, in finalize_options
          ep(self)
        File "/usr/local/lib/python3.11/site-packages/setuptools/dist.py", line 650, in _finalize_setup_keywords
          ep.load()(self, ep.name, value)
          ^^^^^^^^^
        File "/usr/local/lib/python3.11/importlib/metadata/__init__.py", line 204, in load
          return functools.reduce(getattr, attrs, module)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
      AttributeError: module 'setuptools.dist' has no attribute 'check_test_suite'
      [end of output]
  
  note: This error originates from a subprocess, and is likely not a problem with pip.
error: metadata-generation-failed

Bump humanize to 4.x that's the first version where setup.py is mostly nuked and at somepoint in the 4.x series it disappears. The only usage of humanize in this repo is 2x humanize.naturalsize(<some bytes>, gnu=True) which is still supported in 4.x - https://python-humanize.readthedocs.io/en/latest/#file-size-humanization