Fix error in python for installing nf-core on Ubuntu 20.04, python 3.8

gistfile1.txt

Recently, I tried to upgrade [nf-core](https://nf-co.re/) on my Ubuntu Linux but the execution after installation failed with errors from a python module.
Upgrading the python library ["rich"](https://rich.readthedocs.io/en/stable/introduction.html) solved the issue.

Steps below:

```
$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=20.04
DISTRIB_CODENAME=focal
DISTRIB_DESCRIPTION="Ubuntu 20.04.4 LTS"
$ python -V
Python 3.8.10
$ pip3 -V
pip 20.0.2 from /usr/lib/python3/dist-packages/pip (python 3.8)
$ pip3 install nf-core
$ nf-core --version
  Traceback (most recent call last):
    File "/home/nylander/.local/bin/nf-core", line 5, in <module>
      from nf_core.__main__ import run_nf_core
    File "/home/nylander/.local/lib/python3.8/site-packages/nf_core/__main__.py", line 20, in <module>
      import nf_core.lint
    File "/home/nylander/.local/lib/python3.8/site-packages/nf_core/lint/__init__.py", line 21, in <module>
      import nf_core.modules.lint
    File "/home/nylander/.local/lib/python3.8/site-packages/nf_core/modules/__init__.py", line 11, in <module>
      from .info import ModuleInfo
    File "/home/nylander/.local/lib/python3.8/site-packages/nf_core/modules/info.py", line 9, in <module>
      from rich.console import Group
  ImportError: cannot import name 'Group' from 'rich.console' (/home/nylander/.local/lib/python3.8/site-packages/rich/console.py)
$ pip3 uninstall nf-core
$ pip3 install --upgrade --user rich
$ pip3 show rich
  Name: rich
  Version: 12.0.1
  Summary: Render rich text, tables, progress bars, syntax highlighting, markdown and more to the terminal
  Home-page: https://github.com/willmcgugan/rich
  Author: Will McGugan
  Author-email: willmcgugan@gmail.com
  License: MIT
  Location: /home/nylander/.local/lib/python3.8/site-packages
  Requires: pygments, commonmark
  Required-by: rich-click
$ pip3 install nf-core
$ nf-core --version
```