Delete Python 2->3.4 runtime deps and test pins

[webknjaz]

❓ What kind of change does this PR introduce?

• 🐞 bug fix
• 🐣 feature
• 📋 docs update
• 📋 tests/coverage improvement
• 📋 refactoring
• 💥 other

📋 What is the related issue number (starting with #)

Resolves #510

📋 Contribution checklist:

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• I wrote descriptive pull request text above
• I think the code is well written
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  the changes have been approved
• Unit tests for the changes exist
• Integration tests for the changes exist (if applicable)
• I used the same coding conventions as the rest of the project
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• Documentation reflects the changes
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This change is