Downgrade to pycryptodome==3.6.3
Downgrade to pycryptodome==3.6.3

The latest version was leading to compilation errors.
Tested OK with:
```
python setup_testapp_python3.py apk --sdk-dir $ANDROID_SDK_HOME
--ndk-dir $ANDROID_NDK_HOME --bootstrap sdl2 --requirements
python3,kivy,pycryptodome==3.6.3
```

germn/python-for-android,rnixx/python-for-android,PKRoma/python-for-android,PKRoma/python-for-android,kronenpj/python-for-android,kivy/python-for-android,kronenpj/python-for-android,PKRoma/python-for-android,kronenpj/python-for-android,rnixx/python-for-android,kronenpj/python-for-android,germn/python-for-android,germn/python-for-android,rnixx/python-for-android,kivy/python-for-android,rnixx/python-for-android,PKRoma/python-for-android,kronenpj/python-for-android,rnixx/python-for-android,PKRoma/python-for-android,germn/python-for-android,kivy/python-for-android,germn/python-for-android,kivy/python-for-android,rnixx/python-for-android,kivy/python-for-android,germn/python-for-android