text: Title: [Bug] Cannot install, spleeter wants llvmlite 0.36.0 while pulling in numba that wants llvmlite 0.37.0
  Body: - [X] I didn't find a similar issue already open.
  - [ ] I read the documentation (README AND Wiki)
  - [X] I have installed FFMpeg
  - [X] My problem is related to Spleeter only, not a derivative product (such as Webapplication, or GUI provided by others)
  
  ## Description
  
  ```
  $ python3.7 -m spleeter separate -p spleeter:2stems -o output inneruniverse.mp3 
  Traceback (most recent call last):
    File "/usr/lib64/python3.7/runpy.py", line 193, in _run_module_as_main
      "__main__", mod_spec)
    File "/usr/lib64/python3.7/runpy.py", line 85, in _run_code
      exec(code, run_globals)
    File "/usr/local/lib/python3.7/site-packages/spleeter/__main__.py", line 262, in <module>
      entrypoint()
    File "/usr/local/lib/python3.7/site-packages/spleeter/__main__.py", line 256, in entrypoint
      spleeter()
    File "/usr/local/lib/python3.7/site-packages/typer/main.py", line 214, in __call__
      return get_command(self)(*args, **kwargs)
    File "/usr/local/lib/python3.7/site-packages/click/core.py", line 829, in __call__
      return self.main(*args, **kwargs)
    File "/usr/local/lib/python3.7/site-packages/click/core.py", line 782, in main
      rv = self.invoke(ctx)
    File "/usr/local/lib/python3.7/site-packages/click/core.py", line 1259, in invoke
      return _process_result(sub_ctx.command.invoke(sub_ctx))
    File "/usr/local/lib/python3.7/site-packages/click/core.py", line 1066, in invoke
      return ctx.invoke(self.callback, **ctx.params)
    File "/usr/local/lib/python3.7/site-packages/click/core.py", line 610, in invoke
      return callback(*args, **kwargs)
    File "/usr/local/lib/python3.7/site-packages/typer/main.py", line 497, in wrapper
      return callback(**use_params)  # type: ignore
    File "/usr/local/lib/python3.7/site-packages/spleeter/__main__.py", line 114, in separate
      from .separator import Separator
    File "/usr/local/lib/python3.7/site-packages/spleeter/separator.py", line 27, in <module>
      from librosa.core import istft, stft
    File "/usr/local/lib/python3.7/site-packages/librosa/__init__.py", line 211, in <module>
      from . import core
    File "/usr/local/lib/python3.7/site-packages/librosa/core/__init__.py", line 5, in <module>
      from .convert import *  # pylint: disable=wildcard-import
    File "/usr/local/lib/python3.7/site-packages/librosa/core/convert.py", line 7, in <module>
      from . import notation
    File "/usr/local/lib/python3.7/site-packages/librosa/core/notation.py", line 8, in <module>
      from ..util.exceptions import ParameterError
    File "/usr/local/lib/python3.7/site-packages/librosa/util/__init__.py", line 83, in <module>
      from .utils import *  # pylint: disable=wildcard-import
    File "/usr/local/lib/python3.7/site-packages/librosa/util/utils.py", line 10, in <module>
      import numba
    File "/usr/local/lib64/python3.7/site-packages/numba/__init__.py", line 197, in <module>
      _ensure_llvm()
    File "/usr/local/lib64/python3.7/site-packages/numba/__init__.py", line 109, in _ensure_llvm
      raise ImportError(msg)
  ImportError: Numba requires at least version 0.37.0 of llvmlite.
  Installed version is 0.36.0.
  Please update llvmlite.
  ```
  
  ```
  $ sudo python3.7 -m pip install -U llvmlite==0.37.0
  Collecting llvmlite==0.37.0
    Downloading https://files.pythonhosted.org/packages/55/21/f7df5d35f3f5d0637d64a89f6b0461f2adf78e22916d6372486f8fc2193d/llvmlite-0.37.0.tar.gz (125kB)
      97% |███████████████████████████████▏| 122kB 49kB/s eta 0:00    100% |████████████████████████████████| 133kB 49kB/s 
  Building wheels for collected packages: llvmlite
    Building wheel for llvmlite (setup.py) ... error
    Complete output from command /usr/bin/python3.7 -u -c "import setuptools, tokenize;__file__='/tmp/pip-install-7r17xd2s/llvmlite/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" bdist_wheel -d /tmp/pip-wheel-m1g2weyd --python-tag cp37:
    running bdist_wheel
    /usr/bin/python3.7 /tmp/pip-install-7r17xd2s/llvmlite/ffi/build.py
    LLVM version... Traceback (most recent call last):
      File "/tmp/pip-install-7r17xd2s/llvmlite/ffi/build.py", line 220, in <module>
        main()
      File "/tmp/pip-install-7r17xd2s/llvmlite/ffi/build.py", line 210, in main
        main_posix('linux', '.so')
      File "/tmp/pip-install-7r17xd2s/llvmlite/ffi/build.py", line 134, in main_posix
        raise RuntimeError(msg) from None
    RuntimeError: Could not find a `llvm-config` binary. There are a number of reasons this could occur, please see: https://llvmlite.readthedocs.io/en/latest/admin-guide/install.html#using-pip for help.
    error: command '/usr/bin/python3.7' failed with exit status 1
    
    ----------------------------------------
    Failed building wheel for llvmlite
    Running setup.py clean for llvmlite
  Failed to build llvmlite
  spleeter 2.3.0 has requirement llvmlite<0.37.0,>=0.36.0, but you'll have llvmlite 0.37.0 which is incompatible.
  ```
  
  ## Step to reproduce
  
  <!-- Indicates clearly steps to reproduce the behavior: -->
  
  1. Install using `python3.7 -m pip` on Fedora 35
  2. End up with above
  
  ## Environment
  
  <!-- Fill the following table -->
  
  |                   |                                 |
  | ----------------- | ------------------------------- |
  | OS                |  Fedora Linux 35 |
  | Installation type | pip            |
  | RAM available     |                              |
  | Hardware spec     | skylake laptop cpu      |
  
  ## Additional context
  
  <!-- Add any other context about the problem here, references, cites, etc.. -->
  