Fix issue with latest version of cffi

[abhishek-ram]

• Fix the version in the changelog
• Freeze the version of pyflakes to resolve https://github.com/klen/pylama/issues/224
• Update the versions of oscrypt and asn1crypto
• Use SMIMECapabilites from asn1crypto instead of the custom class=

[codecov[bot]]

Codecov Report

Base: 96.48% // Head: 96.45% // Decreases project coverage by -0.02% :warning:

Coverage data is based on head (3b468aa) compared to base (7f11cb4). Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #56 +/- ## ========================================== - Coverage 96.48% 96.45% -0.03% ========================================== Files 6 6 Lines 739 734 -5 Branches 131 131 ========================================== - Hits 713 708 -5 Misses 14 14 Partials 12 12 ``` | [Impacted Files](https://codecov.io/gh/abhishek-ram/pyas2-lib/pull/56?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Abhishek+Ram) | Coverage Δ | | |---|---|---| | [pyas2lib/cms.py](https://codecov.io/gh/abhishek-ram/pyas2-lib/pull/56/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Abhishek+Ram#diff-cHlhczJsaWIvY21zLnB5) | `94.07% <100.00%> (-0.22%)` | :arrow_down: | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Abhishek+Ram). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Abhishek+Ram)

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