[Fix] Add zip_safe option

[Kristinita]

1. Summary

I add zip_safe parameter. pyroma requires, that setup.cfg contains it.

2. Steps to reproduce

I clone update/distribute branch of your repository → I run pyroma in repository folder.

3. Behavior before pull request

D:\sampleproject>pyroma .
------------------------------
Checking .
Found sample
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You are using Setuptools or Distribute but do not specify if this package is zip_safe or not. You should specify it, as it defaults to True, which you probably do not want.
------------------------------
Final rating: 9/10
Cottage Cheese
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4. Behavior after pull request

D:\sampleproject>pyroma .
------------------------------
Checking .
Found pyfancy
------------------------------
Final rating: 10/10
Your cheese is so fresh most people think it's a cream: Mascarpone
------------------------------

5. Testing environment

• Windows 10 Enterprise LTSB 64-bit EN,
• Python 3.6.4,
• pyroma 2.3.

Thanks.

[4383]

Hi @Kristinita!

thanks for your fix.