Conda installation failing due to ERROR 404 missing current_repodata.json

[DarioMarzella]

As for the title, the installation through conda can fail, raising the following error:

`# >>>>>>>>>>>>>>>>>>>>>> ERROR REPORT <<<<<<<<<<<<<<<<<<<<<<

Traceback (most recent call last):                                                                                                                            
  File "/home/dariom/anaconda3/lib/python3.7/site-packages/conda/gateways/repodata/__init__.py", line 132, in conda_http_errors                               
    yield                                                                                                                                                     
  File "/home/dariom/anaconda3/lib/python3.7/site-packages/conda/gateways/repodata/__init__.py", line 101, in repodata                                        
    response.raise_for_status()                                                                                                                               
  File "/home/dariom/anaconda3/lib/python3.7/site-packages/requests/models.py", line 1021, in raise_for_status                                                
    raise HTTPError(http_error_msg, response=self)
requests.exceptions.HTTPError: 404 Client Error: Not Found for url: https://conda.anaconda.org/csb-nijmegen/linux-64/current_repodata.json`

This error seems to be the same as reported by other users on the official conda repository (e.g.: conda/conda#11403 ). In short, it looks like some organization firewalls block the access to current_repodata.json, causing the installation to crash.

Current workaround
If possible, temporarily disable the institutional firewall or install PANDORA on another machine, if you are experiencing this issue.
Alternatively, you can use the Github/Pipy installation described in the README, which will still need conda for the other dependencies but will install PANDORA from the GitHub repository, instead of the conda channel.

Future solution
I am not sure if we can somehow affect this issue in such a way that the json file is considered secure by every firewall and downloaded, but it might not be possible as some users have reported this issue even on official python versions. As such, I will label this issue as 'wontfix' for the time being.