remove newline from easybuild-easyblocks package description (required to avoid installation error with setuptools>=59.0.0)

[boegel]

Fix for error that is raised by setuptools 59.0.0 or newer (see pypa/setuptools#2870)

$ pip3 install easybuild-easyblocks==4.4.2
...   
    ERROR: Command errored out with exit status 1:
     command: /usr/bin/python3 -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-256ka0gi/easybuild-easyblocks/setup.py'"'"'; __file__='"'"'/tmp/pip-install-256ka0gi/easybuild-easyblocks/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/pip-install-256ka0gi/easybuild-easyblocks/pip-egg-info
         cwd: /tmp/pip-install-256ka0gi/easybuild-easyblocks/
    Complete output (25 lines):
    Installing version 4.4.1 (required versions: API >= 4)
    running egg_info
    creating /tmp/pip-install-256ka0gi/easybuild-easyblocks/pip-egg-info/easybuild_easyblocks.egg-info
    writing /tmp/pip-install-256ka0gi/easybuild-easyblocks/pip-egg-info/easybuild_easyblocks.egg-info/PKG-INFO
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/tmp/pip-install-256ka0gi/easybuild-easyblocks/setup.py", line 56, in <module>
        setup(
      File "/usr/lib/python3.8/distutils/core.py", line 148, in setup
        dist.run_commands()
      File "/usr/lib/python3.8/distutils/dist.py", line 966, in run_commands
        self.run_command(cmd)
      File "/usr/lib/python3.8/distutils/dist.py", line 985, in run_command
        cmd_obj.run()
      File "/usr/local/lib/python3.8/dist-packages/setuptools/command/egg_info.py", line 292, in run
        writer(self, ep.name, os.path.join(self.egg_info, ep.name))
      File "/usr/local/lib/python3.8/dist-packages/setuptools/command/egg_info.py", line 656, in write_pkg_info
        metadata.write_pkg_info(cmd.egg_info)
      File "/usr/lib/python3.8/distutils/dist.py", line 1117, in write_pkg_info
        self.write_pkg_file(pkg_info)
      File "/usr/local/lib/python3.8/dist-packages/setuptools/dist.py", line 167, in write_pkg_file
        write_field('Summary', single_line(self.get_description()))
      File "/usr/local/lib/python3.8/dist-packages/setuptools/dist.py", line 151, in single_line
        raise ValueError('Newlines are not allowed')
    ValueError: Newlines are not allowed

(reported by @sassy-crick)

[branfosj]

lgtm

[boegel]

Some more context on this: the newline in the package description was introduced in #2137, so installing easybuild-easyblocks versions 4.3.0-4.5.0 is (currently) broken if setuptools>=59.0 is being used...

[boegel]

There's a lengthy discussion on the breaking change in setuptools 59.0.0 at pypa/setuptools#2893.

Apparently it was very easy to miss this, because the warning message that earlier setuptools versions were producing was not even visible by default...