[ANE-782] [ANE-890] Improves lexer for setup.py

[meghfossa]

Overview

This PR,

• Adds line comment lexer into setup.py parsing, so fossa-cli does not throw terminal error, when line comments are encountered
• Adds \ lexer into setup.py parsing, so fossa-cli does not throw terminal error, when \ are encountered - i.e. line joining in python

Acceptance criteria

• Setup.py parser ignores line comments
• fossa-cli does not thrown an error when line comments are encountered
• fossa-cli does not thrown an error when \ are used for line joining

Testing plan

0. git checkout master && git pull origin && git checkout fix/setup-py-comment-parsing && make install-dev
1. mkdir pr1191 && cd pr1191
2. touch setup.py

for line comment

from setuptools import setup, find_packages

setup(
    name='example',
    version='0.0.1',
    description='Setting up a simple python package',
    author='some author',
    author_email='someauthor@example.com',
    url='https://example.com',
    packages=find_packages(include=['exampleproject', 'exampleproject.*']),
    install_requires=[
        'PyYAML', #
        # 'pandas==0.23.3',
        'numpy>=1.14.5',
    ],
    tests_require=['pytest'],
    entry_points={
        'console_scripts': ['my-command=exampleproject.example:main']
    },
)

for backslash

wget https://raw.githubusercontent.com/zeroknowledgediscovery/Cynet/master/setup.py

3. fossa-dev analyze -o

• It should not throw an error when line comments are included in install_requires block
• It should not include dependency commented out
• It should include all dependency when \ is used to join lines

Risks

N/A

References

• https://fossa.atlassian.net/browse/ANE-782
• https://fossa.atlassian.net/browse/ANE-890

Checklist

• I added tests for this PR's change (or explained in the PR description why tests don't make sense).
• If this PR introduced a user-visible change, I added documentation into docs/.
• If this change is externally visible, I updated Changelog.md. If this PR did not mark a release, I added my changes into an # Unreleased section at the top.
• If I made changes to .fossa.yml or fossa-deps.{json.yml}, I updated docs/references/files/*.schema.json. You may also need to update these if you have added/removed new dependency type (e.g. pip) or analysis target type (e.g. poetry).

[csasarak]

LGTM

[csasarak]

When it comes time to merge this, we should double-check the changelog in case 3.8 has been released already.