Update Conda Installation Instructions

[sudo-michael]

After creating a conda environment and installing heterocl in the following manner

conda install -c cornell-zhang heterocl -c conda-forge

there appears to be a missing module for future

(hcl-test) mike@mai:~$ python3
Python 3.8.8 | packaged by conda-forge | (default, Feb 20 2021, 16:22:27) 
[GCC 9.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import heterocl
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/mike/.local/lib/python3.8/site-packages/heterocl-0.3-py3.8.egg/heterocl/__init__.py", line 2, in <module>
    from .api import *
  File "/home/mike/.local/lib/python3.8/site-packages/heterocl-0.3-py3.8.egg/heterocl/api.py", line 5, in <module>
    from .tvm.build_module import build as _build, lower as _lower
  File "/home/mike/.local/lib/python3.8/site-packages/heterocl-0.3-py3.8.egg/heterocl/tvm/__init__.py", line 13, in <module>
    from . import schedule
  File "/home/mike/.local/lib/python3.8/site-packages/heterocl-0.3-py3.8.egg/heterocl/tvm/schedule.py", line 6, in <module>
    from ..devices import Device, DevMediaPair
  File "/home/mike/.local/lib/python3.8/site-packages/heterocl-0.3-py3.8.egg/heterocl/devices.py", line 5, in <module>
    from future.utils import with_metaclass
ModuleNotFoundError: No module named 'future'
>>> 

This can be fixed by adding the following to the instructions conda install -c anaconda future

[seanlatias]

@sudo-michael thanks for the suggestions! @Hecmay, maybe we should just include future into setup.py?

[hecmay]

Sure. I can update the conda package to include the package.

[hecmay]

Fixed in #332. We do not depend on future pkg anymore.

[seanlatias]

@sudo-michael please give it a try and let us know if it's still not working. Thanks.

[sudo-michael]

It's working now. Thanks!